I mainly race electric indoor offroad racing, and for the longest time I thought that I had plenty of channels and didn't need a spektrum type system. Until a novice drive decided to turn his radio on and put my car straight into the wall (not on purpose) breaking the chassis. It is quite an investment, especially if you have multiple cars, but I believe it is worth it. Just as the previous post suggests, you need correct voltage going to the reiciever along with good connections in order to keep the reciever from going into failsafe mode.
There has been plenty of heat saying that the DSSS spektrum system is not as good as the newer FHDSS systems comming out, but I honestly have been to some big national events and my system has not slowed down because of many spektrum systems chewing up the bandwith.
I think you will see more pros start to use this technology as soon as the radio companys that sponsor them come out with the technology.
-Scott