No Neil, im not saying it tougher to win than SBE and BCA Nationals. No doubt at all that those events are much tougher to win than US Amateur. The US Am is the only one of those events thats a true amateur event. The minute you put a cash prize fund, your mixing pro/semi pro with the amateurs. Take the superbilliard expo. I remember in 2010 the final four had Clatterbuck, Mark Vidal and Tom D'Alphonso. Really? Thats not an Amateur Event.
The OP asked for amateur and pro. Thats why my first response I tried to define the amateur term more because in the USA it holds a very wide definition.