Beautiful mouse with some fantastic extra benefits over the MX Revolution.
I love the thumb scroll wheel, it has the perfect stiffness to it that makes it satisfying to roll on the odd occasion you need to. The traditional noise/response of the mouse wheel getting locked into ratchet mode is back, except now you don't have to press the button to initiate it if you use smart scroll. ka-thunk!
The ability to connect to 3 machines is perfect as I need to connect it to 2 already (and am desperately trying to find a 3rd

) My only gripe here is that I can't remap the button to cycle the hardware to anywhere else (thumb resting button ideally). I often work on both laptop and pc in the evenings, this would be amazing. As it is I have to pick it up, turn it over and cycle the button through the 3 options quite regularly during a session. Not a huge gripe and it is certainly an improvement over the previous gen.
The gesture button is much better than I thought. I am always snapping apps to the left or right hand side of the screen, and the default thumb-left/right-direction is to do just that. You can of course reprogram this to a large variety of seemingly intuitive actions which had me torn initially, but I think it is good out of the box.
LMB and RMB are perfect. They have great travel distance and reassuring feedback. As long as the double click issue from the first gen mx doesn't resurface I'll be happy.
My major gripe is that compared to the last gen MX, it doesn't quite have the same resting position for your hand. I have a claw grip and while it was easy pinching the MX Rev between thumb and pinky/index, this requires a slightly flatter grip. I would advise comparing both side by side if you can before committing.
I was worried that I just threw £80 down the drain for superfluous improvements due to fanboyism, but overall I would say this is absolutely worth an upgrade from the last gen mx (even if some readjustment in grip is required).