I tried my macbook pro with krita, I can't make the stroke smooth like other drawing apps on mac os. Strokes on the left was strokes I drew slow, the others was strokes I drew fast.

This is an issue with us not being able to get the proper tablet events on os x. There's been some adjustments getting it to work in 3.3, but we haven't figured out how to get it as proper as on windows and linux.