Ceuls,
You should sit on each and see what fits you best. The Speedmaster has flat bars and it's a little longer reach from the seat. The America bars pull back more and probably helps if you have shorter arms and torso. I'm 6'2" and I like the fit of the Speedmaster.
The America comes with a two piece seat. You can leave the passenger seat on, or you can remove it for a bare fender look. The Speedmaster has the one-piece gunslinger seat which is unpopular with passengers. The Speedmaster has dual front disk brakes, where the America only has a single front disk. The Speedmaster used to be geared lower, but I don't know if that is still the case. Anyway, that's an easy fix with a different front chain sprocket. Beyond that, it's mostly a matter of cosmetic differences.
Regards,
Cody
