RE: WHICH 7C SHOULD I BUY ??
Richard,
Be aware that the 7C has one major drawback; you cannot set it up for dual elevator servos. Well, you can, but you won't have any trim capability on the slaved side.
Other than that, its a good intermediate radio; I use one as a slave/buddy box for my 9Z, and the grandson flies his Kougar on it as well. So if you don't intend to have a model that uses two elevator servos, you'll be okay. If you do, then spend a bit more for the 9C.