The 'biggy' with 'Spektrum' radios is that they don't require crystals, and that they do their own looking around for a free channel. After that, their capabilities are very similar to many other 6 - 7 channel air radios (gee, wonder why?

). The ability to use 2.4 Ghz for any type model, air/surface, is also nice. The only type model that it doesn't handle well are submarines. The higher frequencies just do not penetrate water as well as the lower frequencies do.
There is a compatibility problem between the DX-6 and DX-7 systems. It has to do with the different signal encoding methods of the two systems. They are compatible in one direction, but not in both directions. That may change in the future, but I doubt it. (Also don't remember which 'direction' is the compatible one, probably the DX-6 can not handle the DX-7 receiver. Do NOT take that as fact!)
Also, please understand that I do have a 'Spektum' radio, and I do like it! They are not 'cure-alls' by any means, but they certainly 'cure' a couple of problem areas for me.
- 'Doc