10 ball,airg,kk,center trac?
In my opinion, a CenterTrak, why? I just do 
Besides, almost every bearing has the potential to be great.
i like anything flat and smooth, with the exeption of ct they are ok imo
Does it make a difference? They all do the same thing, reduce friction to allow the yoyo to spin for extended amounts of time. Of course, it is also your preference, some people like KKs, others like specific flat bearings, and some like Center Tracs. Just try one and see if you like it. 
To quote myself quoting myself,