I've had one for over a year now and LOVE IT!  It's a lot easier to clean than an AR 15 because none of the gas (carbon) ever gets to the receiver.  I use some "aquired" M16 mags from work, and haven't had a single issue in well over 1000 rounds.  I haven't done any heavy-duty firing (1000+ rounds between cleaning), but I would be willing to bet it will make it.