my little appy (got to have QH in him, as he looks a lot like one) has got the BUMPIEST trot ever, his lope isn't bad, though.
i started riding some horses for a gal last week, and the gelding is bumpy, too. his lope isn't bad and man he can run... the younger mare is a lot smoother than he is. have yet to get on the third one.
in comparison my wife's TB has got the world's smoothest trot. i can't NOT post his trot because it's just too dang natural.
it all depends on the horse and how they're built.