First time I'm building a mini ITX PC for gaming. Well, the case didn't give me any trouble at all, it has very good airflow, space for liquid cooling, incredibly low price compared to others, it has air filters everywhere, comfortably fit the graphics card, three SSDs, and has space for a cooler up to 150mm. Highly recommended..

In summary, for the money, this is the most value-for-money SFF case at the moment.

In detail: Being familiar with SFF cases, I have bought and tested many. In this price range, the competitors are the Cougar QBX, the Coolermaster Elite 110, and another Sharkoon, the Zone C10. All three suffer in terms of airflow, especially the QBX.

The QB One has perforated panels on all 5 sides, all with dust filters. Whether you're going for a budget build or more high-end parts, this case will have no problem. A big plus is that it doesn't have tempered glass, so I can easily carry it in a small handbag.

That being said, here are some things to consider:
GRAPHICS CARD - If you have a GPU with 3 fans (which is long in length), the HDD/SSD cages will give you trouble. I had a difficult time fitting my Nitro+ 5700xt, which is a beast, to the point where I was afraid I might damage it. Since I don't use HDD, I removed the cage and now everything fits. With a dual fan GPU, you won't have any problems at all, like with my Rx 580 Nitro. If you have it sitting with the card facing downwards, raise the feet a bit and the card will drop by up to 5 degrees.

POWER SUPPLY - I tried it with both SFX (sf750) and modular ATX (M12 II Evo). If you have a small graphics card, you're fine with an ATX power supply, even non-modular. Larger cards will make cable management difficult with non-modular PSUs.

CPU COOLING - Ideally for this case, you want a top flow CPU cooler (e.g. Big Shuriken 3, be quiet! Shadow Rock, etc.) to take advantage of the 2 fans on the side panel as intakes. You don't need anything else. As for tower coolers, although not in the specs, the Cryorig H7, Arctic 34 eSports Duo, and CM 212 Evo fit. HOWEVER, in this case, it's better to change the direction of the fans, meaning to pull air from the back and make it exhaust towards the front. This is because if you have the normal orientation, the hot air falls onto the top side of the case, where there aren't enough cutouts, as it only has holes for an 80mm fan. This results in the hot air not fully escaping and the temperature rising, even at idle. Now I have it as I mentioned earlier, with the H7 push/pull and one fan as exhaust on the side. The 3700X is idle at 34 and load at 75. These are ideal temperatures, especially for SFF, they are dreamy.

AIO - The only meaningful option here is a 240mm AIO. If you have it blowing air into the case, it will increase temperatures for everything else. If you have it exhausting air, it will fill everything with dust, as you will have negative pressure.

FANS - Don't install the rear fan, it doesn't make any sense, unless it's a Noctua or be quiet! 80mm fan that actually does the job and doesn't bother your ears. On the sides, because the filters are very dense, if you have low-end fans, they will make noise. An ideal choice, quiet and economical, are the Arctic P12 fans. I have Silent Wings 3 now and I don't hear anything, but they are very expensive.

BUILD QUALITY - We're talking about a case that costs 45 euros and does it all. The construction is of high quality and at the same time remains lightweight. It has fallen down and nothing went wrong. If I had to mention one complaint, the power button is a bit flimsy. However, it compensates with the 4 USB ports on the front panel (2 USB 3.0 + 2 USB 3.0).

Conclusion? For me, there is no rival in the SFF category under 100 euros. And this was until recently, when the Coolermaster NR200P was released, which has everything in slightly larger dimensions. The top one for me was the Phanteks Evolv Shift, but we are talking about triple the price and several limitations, as well as a larger size.

A great little box. Slightly larger in size than something expensive on the internet. It can fit a processor cooler up to 135mm with the fan on the side panel or, if the fan is moved to the adjacent position, up to 150mm

It accepts full ATX and SFX power supplies, it can accommodate water cooling and even a dual radiator as long as one fan is slim. The most important thing is that it can fit a 200+mm graphics card (GTX 960 G1) without any issues.
+Solid construction but relatively heavy (made of iron material).
With an SFX power supply, I managed to fit 2 3.5'' HDDs + 1 2.5'' HDD in the front and 1 additional 2.5'' HDD at the back.
Excellent ventilation but poor filtering. It only has filters for the front and bottom.
-It does not accept DVDs and generally no external 5.25'' bays.