Don,
Well...it has been said before many times, but only one company in my book and thats Lightspeed. I have two old set's of the 20K's that still work like new 5 or 6 years later, and was so impressed I bought two QFR Solo's (passive) for the back seat of my Cardinal.
I wore the QFR's one time, and was amazed at how quite and comfortable they were for a non-ANR set. Incredible.
DC's are a great set, but I couldn't wear them for more than an hour until I thought my head would pop. The LS's are much more comfortable.
One think with LS's (except QFR's), if you are tall, the nice padded top makes them kind of high in the cockpit. I found them to be okay for me at 5'8", but taller folks may have trouble. The QFR's are not like that however.