Dwayne (from 4 Star) answered this a while back, and the basic answer was that the Pro line is for businesses that want quick, inexpensive, good quality products, and the Ultimate line is for enthusiasts or those who want more of a show car look. He went on to say that 4 Star Pro sealant won't look as good as the UPP, but still looks as good or better than lots of other sealants out there.
I have no personal experience comparing these 2 products, so I'm just regurgitating. :nixweiss