Welcome aboard Doug.
I've used Noveske barrels in quite a few of the rifles I've built over the years. Most of them for specific SBR's. Other than that, I've used some Armalite barrels, being an Armalite guy, for some carbines (16") and a couple SASS barrels (20"). Granted the SASS barrels use the Armalite adjustable gas system. But other than that, companies like ballistic advantage, faxon and of course Daniels makes some very nice barrels.