Well, if you are one of those who are thinking of buying this mouse and spending 86~96 euros (that's how much it costs today, 20/05/2022), then DO NOT spend it.
First of all, what you have heard about the left click of the mouse that it stops working after a certain period of time like 1 year+ IS TRUE. And I didn't believe it, I thought they just mistreated it. NO, I take care of it as if it's the most precious thing I have, and yet the left click stops working.
What do I mean by stops working? You click it to move a file from one window to another and the click decides on its own to stop being clicked for 1 second and then be clicked again while you hold it, resulting in the file you are trying to move going somewhere else, to another folder for example.
I experienced it in a game too, where I wanted to throw an item out of the inventory and as I moved the item, the mouse stopped holding it and clicked by itself while I was holding it from the beginning, resulting in it grabbing ANOTHER item and destroying a different item than the one I wanted. So, whether you play games or not, the click destroys everything. It also has a problem with double clicking, meaning you try to move the window closer and it makes it full screen because of the double click. Sometimes VERY annoying because it has some crises and keeps doing it constantly.
And I was saying, oh what a perfect mouse, amazing, etc., I will buy it no matter what everyone says. As soon as I held it in my hands, truly the best. Perfect weight, perfect responsiveness, etc. However, UNFORTUNATELY the left click ruins everything after about 1 year.
I don't know if it's worth its money, because for 86 euros that you spend for it to last you a year?? Here you can spend 15 euros for a simple mouse that of course doesn't provide you with all these things, but you have it for 5 years. Here I have some pre-Christmas Microsoft mice that if I connect them, they will work. It's very unacceptable that mice of this category break on their own really. Unless you are one of those who want to spend 90 euros every year, then I pass. Such a shame, once again, such a shame.

Expected Logitech quality which I haven't changed for any reason for 10+ years from the amazing G9 and G9x. However, I had the G903 with the old sensor and the problem I had was that its battery needed charging every 1-2 days. So practically, I always had a cable waiting on the desk, which defeated the purpose of a wireless mouse. Out of the box, the new one has 63% battery and judging from the comments and reviews I've seen, as well as my experience with the G305 which has the same sensor, I see it lasting easily for a few months.

As for its responsiveness, it feels like a wired mouse. In recent years, there have been leaps in this technology and now the differences are very small to the point where they are not noticeable.

The LED lights are complete with beautiful and bright colors.

Also, it seems more sturdy than the old G903 which after a while, the side buttons were somewhat wobbly.

Overall, an excellent mouse and in my opinion, the most beautiful mouse on the market. But, tastes differ.

In relation to the previous G903, it's like day and night. The battery (whoever wants to believe it) was charged on 2/9/19 and today, 12/9/19, it's at 94%. After thinking about returning it and telling them maybe it has a little plutonium inside? (Sounds silly, but I didn't expect such an improvement in battery life from a gaming mouse) It's super lightweight and precise in hand movements, even for a little bit of Photoshop (except for heavy tasks) it's obvious for gaming. There's no reason to get the Powerplay Wireless Charging System. If I encounter any issues with double-clicking, I'll come back here to write about it, although I don't think so because they have made a tremendous improvement.

update: 21/9/19 No problems so far. The battery? It's at 82% with daily use, of course. (the mouse hasn't shut down for a second)

update: 27/9/19 Battery at 72%. In the end, it will surpass the battery life of the mx master 2S.

update: 3/10/19 Battery at 60%. Logitech basically hit the jackpot by releasing the Powerplay Wireless Charging System, really.

update: 14/10/19 Battery at 49%. No problems so far. One minor flaw, if someone wants to point it out, is the freespin mode on the middle click. You have to be a bit careful to "catch" it when opening, for example, a new tab in Chrome. In lock mode, the click is perfect and catches instantly, of course.

update: 21/10/19 Battery at 31%. These days, I've been using it heavily for Photoshop and a bit of PUBG. The battery life is truly unbelievable. (The mouse hasn't turned off for a second since the date of purchase)

update: 23/10/19 Battery at 24%. It dropped from 31% to 24% relatively quickly because the battery hasn't settled yet. I remind you that I haven't done a second charge yet... Truly incredible.

update: 27/11/19
The Logitech G-HUB is a real failure. At random times, apart from the issue with DPI (as I mentioned in the cons), it also loses many settings with its macros. As a result, you have to set them up again from scratch. Truly ridiculous.

update: 27/10/19 Battery at 8%. The dream is over because it's like a dream what happens with this mouse. It lasts even longer than my epic old mx master 2S. Despite the previous G903 being a complete failure, with the G903 (hero), Logitech is years ahead of the competition. I'm putting it on charge now because there's no reason to test it further since I've concluded that it's a fantastic mouse.

update: 7/12/19 I have the impression that with the latest update of Logitech G-HUB, the silly issues with DPI have been resolved.

update: 7/01/20 The Logitech G-HUB, apart from being a failure, often doesn't even open. You have to uninstall and reinstall it from scratch. Literally, and it's not like I open it frequently. Whenever I want to apply settings to an application or check the battery, I open it. The worst part is that there's no option to synchronize your settings when you sign in. So if you uninstall it, you lose all your settings. It has an on-board mode option, and you can uninstall G-HUB, but the cost is not being able to check the battery.

update: 24/05/20 Since the battery has settled, just to give someone an idea of what's happening, it was charged to 100% on 31/3 and today it's at 20%.

Pros:
+ You forget, and to be precise, you don't even remember that the mouse is wireless. It was plugged in for charging at 18:00 from 8% and by 19:00 it's at 70%, and again you forget when you last charged it.
+ No difference in response between wireless and wired.
+ With Logitech G HUB, you have plenty of options such as lightsync with cycle, breathing, audio visualizer, and more. Assignments for any commands you can imagine, even opening the program you want. Multiple dpi profiles, for example, when you open Photoshop, the dpi goes to 600, or when you open a game, it goes to 1000.
+ DPI speeds from 100 to 16000. I didn't have a single miscalculation on two different mousepads.
+ Weight adjustment
+ SUPER LIGHT

Cons: (in my opinion)
- I would like the Bluetooth adapter to be inside the mouse like the beloved g700s. However, it has a small carrying case.
- Sometimes Logitech G HUB freezes and lowers the dpi by one level. For example, if you are in a profile with 2 dpi options (1600 and 1100), it may randomly switch from 1600 to 1100.