I still think that Jackass was the best because it was funnier and had everyone from the CKY movies + Knoxville's crew.
CKY is pretty funny, though.
EDIT: Well crap, I thought only ass was going to be censored. Shoulda tried the test forum first.
All those shows were pretty retarded, but that's just me.
CKY was not a spin off at all. It was out long before JackAs. JackAs had MTV play time, thats why it became popular.