Best are the Mack Mega ones, they're so snug.
Least favourite has to be the ones you get on S&S rides like El Locos and Slammer where the lap and shoulder section are separate. They dig in hard to your shoulders and they don't look sturdy enough to hold your upper body in place which makes me a bit nervous (even though they always work fine!)
Special mention goes to the seat belts on Tower of Terror which let your body float outrageously far out of the seat. I also like how on RMC restraints there's nothing to hold on to so you have to sit there with your hands in your lap. Makes it feel much scarier and more exposed.