This is a fantastic mouse, were it not for a few minor issues, and one glaring one.~Review from a longtime FPS gamer, playing fast-paced arena-style shooters~First off, the Pros:- A plethora of programmable buttons- The ability to program and recall multiple mouse configurations for different applications*- Nice shape and weight: I've heard every complaint and a lot of praise about the shape. I have 20.3 cm hands (can palm basketball), and I do not feel as though it is too small for me. The mouse I came from was a G400s, and I grew to like this shape a lot better. It "forces" you to grip it with something in-between claw and palm grip, it truly is a unique but "good" feel. With the grip I use, my thumb is bent into the side of the chassis, which has a nice textured feel to it that you can dig in to, and my ring and pinky finger are hanging off the edge of the mouse on the side. The mouse is not all the way in my palm by any means, but the hump is just curved enough to provide solid contact with the palm. The whole thing sounds unorthodox, but it allows my thumb and ring finger to oppose each other in near perfect opposition, resulting in a very solid grip where I have a lot of control.- Fantastic sensor.- High quality braided cable for when you do have it plugged in- No discernible wireless lag - I've heard claims you can detect it, don't believe them. Truly negligible to non-existent latency in wireless mode.- Incredible battery, a 90 minute charge will be good for around 3 days of continuous play IME.-The RGB actually notify you of which profile you have active simply by clicking the button on the bottom - very nice.-Great scrolling and hyper-scrolling. (not middle clicks)-Great tactile feel from clicks on most buttons*BE ADVISED: As of the time of this review, nearly a year and a half after the release of this mouse, the Logitech software still to this day is bugged when using the G900. If you try to use the programmable buttons after mapping them to different keys, the buttons fail to respond until you have clicked them continuously several times, then start working again, and this process repeats every time you go a minute or so without clicking them.WORKAROUND: Program the profiles and button commands until you're satisfied, then exit the logitech (blue G) software altogether. There will be another slight delay when you click the buttons again, and once it starts working it stops cutting out. You will have to change profiles using the button on the bottom, and the RGB lights in the middle of the mouse will let you know which profile you currently have active.Now the mostly minor cons:- Construction: It feels somewhat cheap at times, although I think a lot of that has to do with the corners they had to cut to keep the weight down, so with that in mind I can't really mark it as a serious drawback. There is however a slight rattle when you shake the mouse in your hand slightly - something in there needs to be secured better, not sure whether it's the sensor assembly, the battery, or one of the compartments that holds the stuff in place. Needs improvement. Suffice to say, don't drop this mouse.- Right mouse button: For a right-hander, it feels more elevated than it should be. This leads to many unintentional clicks of the right mouse button, with whatever consequences that might entail for your current task.- Clicks: The two side buttons furthest from your palm on either side of the mouse are quite noticeably inferior with clicking action than the nearest ones. They feel stiff and you have to use twice as much effort to depress them. Why not make them just like the nearer buttons? The mid mouse button clicks are equally stiff and frustrating.-Buggy logitech software, as outlined above in the pros. Unacceptable 1 1/2 years after release.-Liftoff distance issues. The liftoff distance for this mouse is quite low, which for me ended up being an issue because adding additional mouse skates for more glide (see below) would cause the sensor to stop registering. Being able to adjust the sensor height would be ideal.And finally, the big con:The feet.For such a game-changing product like this one, with the awesome features it has, they managed to get arguably the most critical element wrong. First off, this mouse has VERY unusual feet/skates (refer to the image linked below). The purpose of all mouse feet is to reduce friction/drag on the surface you're using it on. The G900 fails to deliver in this category. I have tried both the generic feet that came with the mouse, and replacement ones from the only company I could find on amazon that had them, called "Hotline Games". All feet that I tried for the g900 wear out faster than any I've ever seen on any mouse I ever owned, by a large margin. After a week or so of daily use on new mouse feet, the problem occurs.If you're using a cloth pad, you probably won't notice it all that much, but if you use hard surfaces like me you definitely will eventually, when the glide starts to feel "uneven".I wasn't sure exactly what it was, at first. I thought maybe it was the profile button or the on/off switch that was scrubbing the desk, but after covering those two with felt and still feeling the drag I discounted that explanation. So the buttons on the bottom weren't it, but I kept experimenting until I nailed down the culprit: See the V shaped feet in the very center? They go directly below the sensor itself, close to the center of the mouse. For some reason someone thought it would be a good idea to put two wedge-shaped lines opposing each other right in the center of the mouse. Unfortunately not only are the little wedges completely superfluous in attempting to reduce drag, but they cause an outright increase in friction which, due to their notched shape, cause the mouse to "catch" on the surface and gives a rough, scratching feedback. So why not simply remove the V-shaped feet, then? That works, for awhile. With a fresh pair of feet, the absence of the wedges makes the mouse glide as smooth as silk. But after a week or so of wear, it starts to cut into the surface again. Then you turn the mouse over to find out why, and you observe a protruding plastic border that serves as an outline for the inner skates. Once your mouse feet get sufficiently worn down, this plastic border starts cutting into the desk/surface and you are back to square one.I tried swapping/adding additional feet to the mouse, only to run into problems with the low-liftoff distance that made the sensor stop registering even from raising the height by a couple of mm.So sadly, I'm at an impasse with this mouse now after using it for a couple of months. I can either go through 2-4 sets of feet a month (leaving out the detrimental and unusual inner-feet) to remain accurate, or buy something new for competitive FPS and keep the G900 for general use (where it also excels).A very regrettable yet critical design defect on an otherwise groundbreaking product.