I have been using the CEP for about a year now. It is a great system. Flying with the doors off has never been quieter.
I went from the volume on the radio's being almost full on, flying with the doors off (using a SPH-5 helmet), to dang near off. And so far I have not had any problems with the system. My regular partner had one problem with the plug in his helmet that took less then five minutes to fix.