Ergonomically terrific
This trackball is perfectly shaped to use in one hand. With the left/right mouse button under your fingers, and the ball under your thumb it's easy to drag+drop. The selection of extra buttons is reasonable (scroll wheel/middle button, back/forward, and media keys). It's symmetrical, so it works just as well in either hand.
Being powered by replaceable AAA batteries is nice, although that comes at the expense of USB charging. Battery life seems reasonable - I haven't had it long enough to need to recharge yet, but at the rate its going it will last many weeks.
Using Bluetooth instead of proprietary 2.4GHz wireless is good for compatibility. The range is really short though - any more than about 3m and even putting your hand between the trackball and computer can break the connection.
Overall, this is the best remote input device i've used.
Verified purchase: YesCondition: Pre-owned