I've been using Spektrum equipment for years on my tanks.  I like them very much.

I use extra channels to run the lights (I wire them up separately from the electronics) and mute the speaker (handy when I run it indoors or work on it)  I use this to do it. 

I've seen others use extra channels to move the bow mg around, or to animate the commander (he waved his arm up and down).  Imagination is the only limitation.