The mouse came with a broken wheel and after replacement, it came again with a broken wheel. Both the store and Logitech suggest updating the firmware, but the problem is the hardware.
No solution works, neither with cotton nor with paper, all the videos don't work or only temporarily solve the problem.
The ONLY SOLUTION is to buy a Mouse Wheel Board and replace it, costing 10 euros.
Finally, the mouse works as it should, I waited 2 months for it to come from abroad and of course, the quality control that Logitech has done for this particular model is unacceptable. The replacement is easy, but now I don't know how long it will last, but it seems to work perfectly with the green spare part (the one inside is black). However, to be fair to the company, the last 20 products I have purchased from them have been excellent, except for this mouse with the manufacturing defect.

I am probably one of the lucky ones, because I have had it for almost two years and the scroll wheel has not shown the slightest problem. However, in another older Logitech model that I had, there was an issue with the scroll wheel after a while.
The battery management is unreal. I think that if the battery doesn't break on its own, I will need to replace it in about five years.
Weight and size are ideal for a man's hand. Zero mouse lag in games.
Excellent choice.

It's not worth its money at all. Zero durability. Such a reliable company like Logitech is a shame. The scroll wheel broke after 3 months of use. Initially, it didn't respond to scrolling and then it completely broke. Unfortunately, I threw it away without being able to enjoy it.

It seems that ALL G603 have a manufacturing problem with the scroll wheel mechanism. After 5-6 months, scrolling with the wheel starts jumping up and down, making it impossible to use. Logitech's service is simply terrible, the only solution they offer is to do a firmware update - which I tried and it does absolutely nothing since the problem is in the mechanism. Of course, they don't even mention replacing it, they tell you to go back to the store where you bought it and deal with them. After 10 emails with the Indian helpdesk, I gave up. It's a shame because I never had any problems with Logitech products in the past. Stay away from this one unless, for some strange reason, you don't care about using the scroll wheel.

I have had it for 1 and a half years and it hasn't given me half a problem.. not even with the wheel that some people mention here. I bang it on the desk, throw it around and it still works perfectly!!

Update 3 years later:
The mouse still works perfectly. The only thing that happened is that after a fall from the desk, the left click didn't work well. But I opened it up, changed the switch, and it has been working perfectly since then.

First of all, for me it is one of the most convenient mice I have tried. Convenient and very accurate. It also takes rechargeable batteries (although it becomes a bit heavier), and the battery life can only be described as epic.

You don't realize that it is wireless, zero lag (minimal when using Bluetooth).

Unfortunately, its switches are Chinese (D2FC-F-7N) and their durability is poor. In 8 months, the right click stopped working reliably. I ordered the corresponding Japanese ones, which are slightly softer (D2F-F-3-7), to replace them, but I shouldn't have to go through that process. It is unacceptable for Logitech, and it tarnishes their reputation by putting something of poor quality in an excellent mouse. It may be a matter of availability of the Japanese switches, but it is better to have limited availability than a bad reputation.

A great mouse!!
In my hands it is very comfortable, the weight is ideal, it has instant response and satisfactory clicks!
For use in design programs and light gaming it is perfect.
Now if you are looking for the mouse that will make you Shroud....keep looking! You will be searching forever.
As for the scroll wheel that many friends mention, it hasn't caused me any problems (at least not yet).
But it doesn't take any hits or throw it right and left out of frustration in gaming.
I have enjoyed it and would buy the same one again.

The best wireless mouse I have ever used. Before buying it, I was afraid of two things, the problem with the scroll wheel and whether the battery cover with magnets would be stable. The battery cover is stable, but the problem with the scroll wheel appeared after 3-4 months. I contacted Logitech and they sent me a new one within a week. In this specific mouse, the problem with the scroll wheel is easily solved since the cover comes off easily due to it being magnetic. I sprayed some contact spray on the scroll wheel mechanism (as we look at it, the scroll wheel mechanism is on the left) and for the past 5-6 months, the scroll wheel has been working perfectly. Do not attempt the interventions shown on YouTube on how to fix it. With a little contact spray, you are ready to go.

In 1.5 years and in my case, without ever using it for gaming, the wheel broke. FAR AWAY!

The mouse is generally very good at everything except for its durability, unfortunately the wheel died after 6-7 months

Powerful mouse, with excellent response. The battery easily lasts 2 years in lo mode and 9 months in hi (12,000 dpi). If you're not interested in rechargeable ones & want batteries, it's the best value for money. It needs a little attention to falls, because the lid opens and closes with magnets, to reduce weight. Ideal for those with relatively large palms. Buy without fear before it runs out.

I initially bought it for its price and because it is wireless. In general, because I had experience with previous mice from the company, one of which lasted me 11 years, I trusted Logitech again. Good weight for me at 125g, the battery is indeed epic (I have had it since October and I haven't changed them yet, and I never turn it off from the bottom) and this applies of course to the normal mode. It also works with one battery for those who want fewer grams. I would say it is quite a good value for money for a wireless mouse. The only negative is that sometimes in very few cases I lose the cursor in the game. Beautiful design and nice cover for the batteries which opens and closes using 2 small magnets. I recommend it for this price and for people who do not have excessive demands. Otherwise, we move on to more expensive models

After 1 month, the wheel of the bike broke while I was riding it uphill, and it was going up and down on the screen. I thought it might be a software issue and kept it for half a year, but after a lot of searching, there were many comments that it is a widespread problem, so I returned it due to the warranty and bought another model. Also, after holding it for a while, my tendons in my hand hurt and the logo easily fades

I bought the mouse as a so-called gaming one, but I ended up getting rid of it. It was heavy, not user-friendly, and had mediocre response. The scroll wheel made the screen go up and down inconsistently. It's not at all durable, which is something that can happen with a wireless mouse or something else. Overall, I am very disappointed with my purchase. Of course, this is just my personal opinion, and I'm not trying to discourage anyone from buying it.

The mouse is generally very good.
It gave me a problem with the scroll like a child in a previous review.
However, I contacted Logitech and they sent me another one within a week, without taking the old one back. Meanwhile, I found a way to fix the problem myself. Although it seems to be a software problem (since the update fixed it for a while), in essence it is a hardware problem and the solution is provided by the video I have included below. So at the end of the day, I have 2 functional mice.
https://www.youtube.com/watch?v=38Bs8e9QQ1E

My only objection to this mouse is that it slips a little in the hand and may be somewhat large for my standards. As for its performance and technical characteristics, there is no other observation I can make. It is excellent in all aspects. Excellent value for the money. I am revisiting my initial review and after some time of use, I have noticed that there is sometimes a quite annoying noise coming from the plastic material that the mouse cover is made of - which you should know is not stable but magnetically attached to the mouse - when the side buttons are pressed.