The TT Pro series are good engines. Stay away from the GP series. Magnum engines run well and the price is right. I have run several Magnums and they all have run well. The only Magnum I don't recommend is the 1.80 2 stroke. Enya and Super Tigre are very high quality engines and they run very well also. The OS LA series run ok, but they are not Ball Bearing engines. They use a bronze bushing to support the crankshaft. This bushing tends to wear out causing erratic idle and can be messy on the front of the plane. The cost difference between a Magnum 40 BB and an OS LA 40, not enough to worry about. The bearing motors will last much longer and provide more power.