I'm still a beginner, so i really don't need lots of power yet, but i do like to pop the heli in the air already and the 39 gets bogged down doing it. I believe the extra power makes the settings more forgiving. I know it works that way for airplanes. higher power to weight ratio means i don't have to push the engine as much to get what i want, so it stays cooler, and of course is more fun. The 50 has the bigger engine of course, bigger blades, longer boom and slightly different gears but is the same frame and mostly the same parts as the 30 so it weighs just 6.6 pounds, (most 60's are around 11 pounds (?)) and parts are still cheap.

I have a freind who is a pretty good pilot, does a lot of agressive aerobatics. He has a 32 rappy, a 50 rappy and a YS 90 powered Frea (?). He loves the Frea, but flies the Rappy 50 the most.

I hear the rappy 50 also does auto's much better, not sure if it is the lighter wing loading, or better rotational inertia from the bigger blades, but the rappy 30 is notorious for running out of steam on autos.