I find some players, regardless of 3.5 or 5.5, can handle body shots really well, while some other's can not, almost fall over themselves trying to get out of their own way.
Makes a difference.
Same with the first serves. Some reach better to return, while other's have a spot in space then can defend REALLY well, while leaving other spots almost unguarded.
Or maybe I"m just overanalysing the situation, and I should just shut up and get in shape.