I prefer a trackball because I can momentum-flick my cursor from one side of my 4k screen (at 100% zoom) to another side monitor pretty easily... as long as I keep the ball bearings clean. I've been thinking about using a metal trackball for more momentum, but haven't gotten around to it yet.

I have a "sniper" key I use to decrease sensitivity for more precision cursoring... but rarely use it (maybe once a month?). I do not have thumb fatigue.