Personally, though it may not be the best thing to do financially, i'd start with a superjet. Learn how to do barrels rolls and such and beat it up. Once you get your grove and get things dialed in, buy an aftermarket. Once you switch to an aftermarket you will be able to do those same tricks, but better and with less effort.
Thats an opinion, but at the same time it wouldn't kill you if you just bought an aftermarket. It really all depends on how much money your wanting to throw around. While your "learning" which takes quite a while, theres nothing you will be able to do on the aftermarket hull that you won't be able to do on a superjet.
I'd spend a season on superjet, learn the fundamentals of riding then maybe next year if you feel like you want to get more involved and progress more jump into an aftermarket.