Just a quick chime-in re Magic Mouse ...
I've had same since 2011 and no complaints. It was rough on non-rechargeable batteries — alkalines lasted only 2 weeks.
So I got an Apple Battery Charger (Model A1360 - MC500LL/A) which came with 6 AA NiMH batteries (which show no sign of wearing out).
Over the past 7 years and over 120 charging cycles I've gotten an average of 3 weeks (20.6 days) per charge on same. Not too shabby.
