First of all, it's the best for its price. I've had it for several months and I've noticed both positive and negative aspects.
Positives: really fast refresh rate and nice vibrant colors, the curvature is just right and it looks very natural to the eye.
Negatives: significant light bleed (meaning when the screen is completely black, the light from the top and bottom parts of the screen is quite visible - the more you're in an incorrect position, the more noticeable it becomes). Unfortunately, it's a VA panel, so there is a difference in colors and quality compared to an IPS screen. Both motion blur and ghosting are present and noticeable in demanding games in terms of the speed you need (warzone, fortnite, cod).

It's worth its price, it's a very good choice to step up. Its freesync is flawless, it gives more fps and is really well-made. Its negatives don't make me want to change it or anything. Just some of them (e.g. light bleed) shouldn't exist. You already know the rest when you choose the cheap option on a VA screen.
P.S.: The program for settings needs some improvement

I have had the screen in my possession for 3 months now and I am completely satisfied. It is truly an amazing choice for anyone considering such an upgrade. Personally, I come from a Samsung 24" 60 hz and the difference is huge!

- As for the visual aspect, the screen is a gem on the desk. At first, I was concerned about the size, as I have a small desk (120x60cm) with the tower on top of it. In the end, not only does it not take up too much space, but I can actually say that the desk is more comfortable compared to the previous flat screen. The construction, although plastic, gives a premium feel. Very sturdy and beautiful stand, with comfortable rotation and height adjustment of the panel to suit your needs.
- The curved panel is not so aggressive, resulting in it not being so bothersome for office work, browsing, and watching movies or series.
- For a VA panel, it provides a very good image and colors even without calibration (if someone wants to calibrate the screen, there are corresponding tutorials on Google and YouTube). Personally, I am satisfied with the results and have not adjusted it yet.
- The 2K resolution really gives a different feeling, especially in gaming.
- Comfortable to use even after many hours in front of the screen.
- The 1ms (MPRT) that the company claims is actually 4ms (GTG), which personally I don't think anyone will notice during gaming (either multiplayer or single player).
- I have not noticed any ghosting in any of the games I play.
- Yes, there is backlight bleeding, but again, it is not something that someone will notice during gaming, except for loading screens and Windows startup.
- The brightness of the screen is fine in both dark and bright rooms (various comments had worried me for no reason).
- The viewing angle is also very good, the colors and image do not distort much. You can comfortably read text or watch videos even at a fairly large angle.
- I haven't really touched the menu much, although from what I saw, I wouldn't say it's too difficult to use.
- The curved version comes with speakers, which are not the best, as they do not have clear sound and have weak volume for music, movies, and gaming.

Let me clarify that I am an average user who is into gaming but also does office work due to my job (Microsoft Office, design programs, etc.) without demanding too much, but still wanting my money's worth. I really achieved that with this screen, as I didn't want to go over budget.
The screen is an absolute value for money, with future-proof features. I highly recommend it! 5/5!

I have had the screen for a month. Transition from a 23" full HD 5ms monitor, the visual difference is huge in all aspects, from design to resolution, where it is on another level. It is clearly enjoyable in games and less so in office work, where it does not disappoint. The only downside is that the buttons for the menu are unacceptable, they are too small and in the wrong position. However, you can manage with the software you download from their website. I highly recommend buying it, especially for children, as it costs less than 300 euros and there is no other monitor at this price with the same capabilities on the market..
Edit 19/3/21. After 8 months of heavy use, the screen has not presented any problems whatsoever.
Edit 7/6/24 Unfortunately, I agree with the previous review and I will lower the rating I had given because, unfortunately, after EXACTLY 4 years, the screen failed in terms of reliability as suddenly all the image inputs, display port and HDMI, stopped working.... It's a shame because otherwise it was a decent panel.

The screen is an excellent value for money choice. Personally, I upgraded from a 1080p 75Hz IPS with 5ms response time to this one and the difference is chaotic! It's truly a huge leap in quality and experience. The only thing that took time to get used to was the size, in my eyes, the 24 inches and the 27 inches had a significant difference.

The image is beautiful and sharp with nice colors. The construction of the screen looks high-quality and sturdy. The unboxing was pleasant and simple, while the assembly was very quick as the arm of the stand connects to the screen easily. Plug-n-play experience, no issues, worked from the first moment. With the G-menu driver/software, you can directly and quickly adjust the settings (brightness, colors, etc). It was immediately recognized by Windows as 1440p 144Hz as well as the model, no problem.

Regarding the brightness, many people talk about it, but I haven't encountered any issues (I keep it consistently at 50, lower it a bit at night as I have sensitive eyes). It should be noted that I have a window (balcony door) behind my desk and I have no issues during the day. Also, the annoying reflection that my previous screen had on the left due to the light from outside has been almost completely eliminated with the new screen (this is mainly due to the curve and maybe the panel difference).

FreeSync also runs without any problem from the first moment, its support was immediately recognized by the Raden Software and activated automatically.

In the games I have tried and play (Witcher 3, GTA V, Shadow of the Tomb Raider, CoD), I haven't encountered any issues and haven't noticed any ghosting. Of course, as I mentioned before, I come from a 1080p IPS 5ms, so the response times ultimately don't differ.

Overall, I highly recommend it. I did a lot of research before buying it and although people spoke highly of it and said it was worth it, they emphasized some weaknesses. Personally, I haven't found any of these weaknesses so far and it's better than I expected. I am very satisfied, at this price (290) there is truly no competition. 1440p 144Hz with FreeSync Premium from a reputable company. Over time, I will also provide an update.

Let's start from the beginning then.

*First look
I bought it for 275€.
Visually, it is a beautiful monitor.
Fantastic design.
Very sturdy construction, from the stand to the back. Very high-quality material.
Its screen is completely futuristic.
Curved without a frame. A masterpiece.
Very vibrant colors and very deep black! A surprise for a VA monitor! Almost zero backlight bleed! Amazing!
I could compare it because we have 3 panels in the same office.
-TN Asus PB277Q
-IPS LG 29UC88
and now this one. VA.
Honestly, at 37 years old, playing games on a PC since I was a child and having played on several monitors of this budget, I have never seen such deep black on a monitor.

*Desktop/workstation
I don't think it is suitable for this use. It has the lowest brightness on the market.
During the day, it is difficult to see with the brightness at 100%! I mean it.
Its brightness will shock you during the day.
It is purely a monitor for a dark room.
Now, if you work on your computer at night or in a dark room, then it's okay, it suits you.
Also, even though it is a VA panel, it does not have good viewing angles as it should.
It will make it difficult for you to watch movies.

*Gaming
For casual "sofa posture" arcade gaming, it is fine.
For demanding/competitive FPS online multiplayer, it is not suitable.
Its response time is 1ms MPRT and NOT 1ms as advertised.
It is a marketing trick. It is a different unit of measurement. 1ms MPRT >= 4ms.
Specifically, this one is 7-8ms. As a result, ghosting in fast-paced games becomes prominent.
In first-person shooter games like CS and COD, with 8ms, you see ghosts when corner peeking.
For strolling in the battlelands of BFV, it is okay.
Also, VA panels are widely known for their high motion ghosting in moving objects in games. They leave a trace after the movement, resulting in a lack of clarity in the image. Commonly known as motion blur. It is basically the trade-off you pay for the image and color quality that VA offers compared to TN.
Also, its Display Port is version 1.2. (DisplayPort 1.2 supports up to ≈165 Hz at 1440p).
Personally, I don't find it backward or negative, since to achieve 2K 165hz, you need a PC UFO with a CPU of €600 and a GPU of €1500.

*Curved
On a 27'' 16:9 aspect ratio monitor, it is ridiculous. It doesn't give us anything in essence. It is for impressing our clueless friends or ourselves when we look at it like a vase.
Curved was exclusively born for Ultrawide 21:9. That is the reason for its existence. To bring the edges of the monitor closer to you, which are far away. Even then, for it to be functional, it needs to be aggressively curved.
I mention this because you pay for it. It is in its price.
It would have been better if they had invested in the response time.
It is pointless. Only for aesthetics.

*Menu
Its manual menu has a terrible navigation. It's frustrating.
It is 2-button controlled instead of 4 buttons (or a cross), which most monitors usually have.
Of course, AOC released software (AOC G-Menu) where you can save up to three custom settings in three profiles. For example. Game Movie Reading

__________________________
*Overall comparison
Until today, April 9, 2020,
studying humbly 2 weeks of benchmarks, comparisons, reviews, deep analysis, specs, etc.,
the best gaming monitor for 2020 with the following features:
-16:9 aspect ratio (NOT Ultrawide 21:9)
-27''
-1440p (2K, QHD)
-144Hz
-Freesync/G-sync (you won't see over 100 fps though)
-Up to €600
are clearly the 6 options below. The order is random.
__________________________
#1.
€305
AOC CQ27G2U (VA panel)
(MID performance & MID image quality)
+ Best contrast, Best deep black, Vibrant colors, Low cost, Curved (for aesthetics only), Ergonomic stand
- Response times 7-8 ms (ghosting), 12 ms input lag, Blur, low brightness, Display Port 1.2, terrible navigation

#2.
€340
Dell S2719DGF (TN panel)
(TOP performance & WORST image quality)
+ Best response times 1ms, 5ms input lag
- Worst image quality (faded), Inaccurate colors, Smallest viewing angle

#3.
€375
Viewsonic VX2758-2KP-mhd (IPS panel)
(Tricky performance & TOP image quality)
+ Very high-quality image with color accuracy, huge viewing angle, 8ms input lag, Display Port 1.4
? Response times, 4ms at 144Hz with 15% ghosting and 7ms at 120Hz with 0% ghosting
- Backlight bleed, Non-ergonomic stand, terrible navigation, unacceptable speakers

#4. (2021 update!)
€400
Gigabyte M27Q 27" Gaming Monitor (IPS panel)
(TOP performance & TOP image quality)
+ AMAZING. The best GAMING! monitor on the market within a €400 budget. It's killer! It's epic. No discussion.
- If you're buying a monitor for productive work or anything else that requires a lot of reading and typing, it's important to choose a monitor with an RGB subpixel arrangement for clearer and cleaner text. And NOT BGR like this one. Monitors that use the BGR subpixel arrangement instead of RGB, like this one, display blurry text, as Windows are designed to work only with the standard RGB arrangement by default.

#5.
€535
LG 27GL850-B (IPS panel)
(TOP performance & TOP image quality)
+ The highest-quality image with color accuracy, huge viewing angle, Response times 3-4 ms, 8ms input lag, Display Port 1.4
- High cost, Backlight bleed, Worst black color

#6.
€590
Asus TUF Gaming VG27AQ (IPS panel)
(The ultimate flagship, IF you don't get a monitor with 1-2 burnt pixels AS USUAL!)
__________________________
Overall, the AOC CQ27G2U is a mid-range level monitor, with G2 technology, beautifully aggressive curved, and its price is fantastic for the mix of good image and performance it offers.

The available budget, then, is ultimately what determines everything.

AOC CQ27G2U benchmarks
https://www.youtube.com/watch?v=RNsNOyArB9A&t=891s

about curved monitors in general
https://www.youtube.com/watch?v=cnTkbA-E5L8