Haven't tested my 15 vs a a 13, but it gives me enough low-end vs my 12m to justify owning one. That being said, don't expect miracles from it, at 200lbs I'm still on the 15m and a 133 tt, when regular small-ass'ed Joes are on 10-12m Cabs. It has some low-end torque, but it is not by any means a light-wind kite. I have a 70kg friend who rides a 12m rebel, and by the time he can't go upwind anymore, i'm long gone packing and smoking bamboo... though with 4m extensions I can usually pretend like i'm keeping up... On the other hand, it's the most fun 15m I ever flew, and it loops like a charm. Also, it's the best kite i ever had a chance to do a downwinder with.