The .72 will work fine and hover fine. but the .91 and 100 give you a little more reserve when you really need it. when you start hovering low it's nice to have the power to bail you out. it is worth spending the extra $15. i've let a friend fly mine that has a .72 and he says mine moves a little crisper and with a lot more authority. It's all about preference. you can do the same moves with the .72 it's just a lot more fun with the .91