i defer to boogiedown and surnli, as far as single fin expertise and experience go. i will just say i enjoy my 7'2" single fin very much. i ride it in knee to head high (rolling, mushy, not hollow, tried that, scary). we never bring it on trips, which is dumb, b/c both RD and i inevitably say, "gee, this would be even more fun on red rocket!" we just can't let go of the idea that when you travel it will be good enough to always ride something short. then we get skunked, LOL! and of course its easier to take something shorter and i would also be devastated if red rocket got damaged by the airline.
compared to a thruster i did find it very squirrely at first, but that may also be b/c of the design of the board, which is a displacement hull (kinda convex) and 50/50 rails. as for speed, a fish with a twin fin setup or RD's spectrum (80s thruster with glassed on fins), are also very fast, particularly on the takeoff.