This mouse is great. The shape fits my hand perfectly and is the first mouse
I've ever used that is big enough to rest my entire palm on without my fingers
overhanging. The button placement is good too, making it easy for anyone with
medium or large hands to reach all buttons. All the grips are comfortable and
the materials seem to resist dirt easily. I haven't turned it off in the
2 weeks I've had it and it still has just over half the battery life left
(using both modes). It glides quite easily which offsets its weight
slightly.
There are some down sides though. I don't think it would be very easy for
someone with small hands or short fingers to use. It is quite heavy, even
compared to other wireless mice I've tried, and the only way to fix this is by
removing a battery. It's not very comfortable or easy to use all buttons with
just a finger grip, you really need to be comfortable with using a full palm
grip. It only has room for 1 on-board profile. I previously used the G300
which has 3 on-board profiles. Only having the one has limited a lot of the
extra use when not running any specific application.
Even with the downsides this is the best mouse I've ever used.