I really like mine. Though I've run only about 300 rounds through it so far, it ran great. I've got the older style with the bolt carrier that has a staked blank gas key, instead of the newer version with the one piece carrier. I've not seen any hint of bolt carrier tilt.
The best part, of course, is that by rerouting the plumbing to the front instead of the back the upper/lower receiver assembly, bolt carrier assembly, and internal bits stay *much* cleaner. No scraping carbon deposits in/around the bolt and bolt carrier. Some guys on here say they don't care, it isn't a problem, etc. But each to their own. I prefer not having to spend an hour cleaning the BCA alone. Which I DO on my traditional ARs. My only wish is that I could find one of the Colt piston uppers with the 14.5" barrel. Been looking. Making inquiries. No luck so far.
I hope you get your questions answered.
R.