I recently switched the summit over from 27mhz to 2.4ghz. I really like the non-interference thing cause everyone and their dog has a traxxas Am radio it seems. Anyways, I was reading the radio literature that says it can remember 20 models (I think) so I bought a bunch more receivers for my other trucks--so far I am very happy with the conversion.
I was using the spektrum dx3.0 and was not really thrilled with it--8 batteries, 4 model limit with some goofy menu you had to flick through to get to each one and 3 channels that weren't very straightforward to use (i like switches and toggles--thats it) I liked all the end point adjustments etc but never used them so there ya go..The receivers were also hard to find used (where I am)
The summit radio is 5 channel so there is lots of extra channels for remote lights, winches, other goodies. Once the receiver is setup for the vehicle, the radio remembers which vehicle its talking to. The only thing to remember is that two vehicles can't be on at once and the radio has to shut off before switching models--not really very big limitations as far as I can tell. The receivers are what 30 bux each new or so? and if you buy 4 or more from tower they give you a bit of a discount. I'm now building a scale tow truck with the usual steering and throttle but can now add a bi-directional winch, rotary flashing lights, rear spotlights and running lights and maybe one other goodie. Love not being limited to 3 channels!
Anyways, just thought I would pass that one for anyone thinking of switching over--ditch the spektrum/AM and try out a traxxas 2.4ghz radio if the above sounds like it would fit your needs.