Pyro,

The CP+ has a mixing system thats called Hiller mixing and is easier to fly for the beginner. And the CPP has a system called Bell Hiller mixing and the response is quicker and usually harder to control for the beginner. I was also thinking there was something different about the transmitters too, but am not totally sure. The CP+ might also have flat bottom blades, but I haven't checked into it.

Nick