Hello, I've read the thread how to select your first radio, and I've got it narowed down to a Specktrum 6si or a 7s. Can someone tell me the difference between the two other than 1 channel and the model memory? I don't want to buy a radio that I will want to replace in a year. I plan on staying with the hobby, so I want something that I cAN "grow into". Does the 7s have a lot of features that I would nerer use? Or is it a good investment?