Stalling the bike regularly is a technique or machine setup problem, address that first. You don't need to be throwing marks away simply because your idle speed is too low or your clutch is dragging.
Just to add I have had the exact opposite experience to nickc1969. My beta is amazing at grip finding!
The point being there is no "best" bike (silly question really) each bike has its own traits which suit different people.
Buy the one you like the best.
If the stator is failing (which is very common on these shercos) it may cut out when hot, and restart once it has cooled off slightly.
However I would start with a full carb/filter clean & tank flush, then go from there.