A 3 port Nova or RB is hardly a low end motor. The S5 is a great motor to start with. They're about $220 , real close to the +4's price.
The +4 is well below $300. I just go with the higher end motors because they seem more reliable and easier to tune. I never could get a RTR engine to run well. And then there is the extra lifespan Nova and RB are known for.