If I recall correctly, the CENs either come with a Skyion Radio which I think is now FM, or the Airtronics MX3 radio which is FM.
The main issues with the Matrix TR is that you need to buy the CNC steering arm part. The plastic ones don't last very long. Also, they use a 23mm hex which kind of sucks for wheel choices as the big thing now is the LPR setup, 17mm. For the RTR, you will want to get a conventional air filter right away too.
The Matrix's can take a pretty good beating. I know a guy with the Truggy and my former Matrix Buggy and he beats the living crap out of them, and they do hold up much better than what I would have expected or have seen of other vehicles.
Performance wise they will get you around. Are they top flight? probably not, but, if your skills are up to it, you should be able to make the podium, same pretty much with any race vehicle. I liked the matrix I had as it was very neutral feeling around the track. Does it compare to my RC8 in the steering department, no. But I didn't feel overly outclassed against say the Jammin, Mugen, etc.
If you look online, especially ebay, you can actually find them VERY cheap, even new very cheap. I was very suprised by this.
Main thing is go with what you can get parts for. Me, I have no LHS, so it doesn't matter. For you though, if you have the parts on the wall, its really helps especially if you are on a budget.
Personally I would buy one used, buy a NEW engine as that is the part you should buy new unless you know the guy, and do a rebuild and clean up of the vehicle. You will save a good amount of money that way.