im with murph.... get two of the same... makes tuning alot easier and shared parts at the track. ST1 would be my choice if youre on a budget Hypers do have crappy engines (I have a Hyper with an Axial in it and I love the thing) Losi is a bulletproof choice nice engine, nice engineering parts are everywhere.
I just got and ran my Turmoil Pro today and absolutely love the thing and they are cheap as rollers right now on Amain. not had it long enough to say go get one but I am liking mine. whatever you get there are loads of people here to help you out so youre kinda safe just depends now on how much money you want to spend. good luck