It's sort of the Ford, Mercury, Lincoln comparison!! If you're just looking for the absolute basic, go with the EXP! Want it a bit better, SLE. Top of the line, "B" series! You'll also notice availability of more submodels as you go up the ladder! The "B" for instance is offered in 3 versions, std, mid, full vent, better able to pick out the correct sail for that days wind conditions! SLEs are in 2 versions, std and full vent, and EXPs are in one model, std!!
Are you anywhere near SparkieRob or West Australian?? Two members of this and the Kitelife forums, from "down under", they would (I'm sure) let you have a go on their kites, before deciding!
No matter what you get - welcome to the world of Rev!! The Darkside Rules!!