[This review was collected as part of a promotion.] Overall pretty good. Battery life has been killer so far, the white hasn't stained in the last month, and I hope the new materials don't wear down or get sticky. My only three complaints:
1) low polling rate. Hopefully this will be fixed in the next gen with a new bluetooth revision 2) Haptics are a bit underused. Mostly I write code and use Google Chrome, and there aren't good haptic plugins for my programs. 3) Build quality nit: The left and right click buttons are slightly misaligned with each other vertically at the tip, resulting in a height difference I can see and feel.
The mag scrolling is great, the repositioned thumbwheel is nice, the new gesture button is good, and the action ring is cool once you customize it.
The mouse is famous for a reason, all the features are amazing. My favorite thing about the mx4 is how comfortable it is over extended work sessions. The "click" is the best feeling. Its a beautiful mouse and the new materials stay clean for wayyyyy longer and are way easier to clean. I got the non-mac version to get the USB C dongle and it works flawlessly on my Mac Mini M4 with the logi+ app.