Add my 2 cents.
Coming from my second g9/g9x mouse with the inevitable cord failure design flaw...
G502 does seem to track better.
Didn't take me that long to get used to the feel and size, its somewhere between the two grip sizes of the g9x, so its not super big.
All the buttons activate easily, wheel is firm and easy to actuate as button and tilt buttons, no mushy wheel nonsense there, just like the g9, so you can bind game functions to it for decently fast response. The wheel is very stiff in the non free spin mode though, so whether that works for you is personal. But the free spin mode works great, and finally the toggle for the mode switch is on top, not the silly underside of the mouse of the g9 series.
The extra buttons are easy to reach, a nice advantage of 1 additional easy to press button vs g9 series, the dpi buttons can be rebound as well but I find those harder to reach, so I only use them for relatively unimportant binds.
The lighting can be controlled better now with the bios update, can pulsate and control brightness.
I do miss the customizable colors of the g9 series, helps identify the profile you are switching to automatically, verifies the driver hasn't frozen. But the dpi leds do blink on application profile switching so there is some indication that its working.
All in all it seems like a good mouse so far. They've both thickened the braided cord, added better strain relief and the cord is more supple, the g9 had a cord that held the factory packaging kinks for years if allowed to. So hopefully the cord doesn't have the same flaw of the g9 series.
Dpi buttons now being relatively easy to reach are more useful now in general, I bind them to other features since I never change dpi anyways.
Decided against a 602, I don't like thinking about batteries, it lacks a spin wheel, and unless you play games that require that many buttons, I have doubts about quick thumb activation of a double row of thumb buttons, makes them less useful in stuff like shooters where its about reflexes.
Logitech makes good mice, but they are never perfect it seems. Things got a stiff wheel, and no color leds. Planned obscelescence seems to be the thing...
Also, could have benefited from the mx revolutions auto shift wheel...