The G502 uses a brand-new sensor, unlike anything else currently available on the gaming market. This is an optical IR-LED sensor, which Logitech and PixArt developed together, so it's most likely going to stay an exclusive. Since this is the first time I'm using such a mouse, I'll have to play around with it a little.
First, I'm using NexuiZ and Quake Live to see if I can notice any mouse acceleration (alas, I have no proper tools to test acceleration), and then rely on the ever accurate Paint for jitter and prediction.
Since, I do not have the adequate eqiupment to record the mouse movement alongside the movement on the screen, I cannot do anything more than just express my overall experience whilst fishing for acceleration. I played quite a lot of TF2 and Counter Strike: Global Offensive (Source Engine supports raw-input after all), and I can safely say that if the sensor has some acceleration, I didn't notice it.
Jitter nis caused by the sensor registering noisy data. It's usually comes out as small deviations, along both sides of a line. It isn't something you might notice in-game (or with mouse smoothing turned on), but if you're using raw-input, usually drawing and design applications are sensitive enough to pick it up. The results are also influenced by the DPI and Response Rate.
There's absolutely no jitter, even at 9K-12K DPI settings, where even my shaking fingers are registered.
What about prediction? Well, the sensor doesn't have any, but I can't say that I'm surprised.
I daresay, this PixArt sensor seems to be one of the best sensors I ever played with.
I hope G502 is going to be a standard to which future gaming mice will be judged against. It's an absolutely fantastic mouse outside the gaming scene, but where it truly shines is in-game. The almost perfect sensor makes it behave exceptionally well in shooters, especially the ones working with raw-input, like Counter Strike: Global Offensive and Battlefield 4.
While it has fewer buttons than your average MMO / DoTA mouse, the software package is exhaustive enough to allow you to tweak it according to your play-style.
The only problem that I see with it is the overall size and weight. While I am not bothered by it, low-sensitivity players will have some pretty serious issues dealing with this rodent, especially in prolonged gaming sessions.