Trackball.
Ok. Which trackball would you use, if you could have any single trackball for free?
I'd be happy with any of the 3" happs, wicos, or betsons TBs. If push came to shove, I'd probably get the happs high-lip (aka golden tee) trackball.
BTW, is the Happs 3" the same thing as the Atari 3"?
Yes, the happs 3" normal TB is the exact same case as the original atari 3", but with different optical boards.
And the newer happs models, "high lip" (aka "golden tee") and "high ball", are almost the same too. They differ from the normal normal happs model by
one single piece: the top-half of the case. When they're mounted correctly, the user cannot tell the difference between the normal and the high lip models; however the high ball is different in height and feel.