Anyone own one of these things? What is your opinion of their quality? Fit and finish? Do they operate flawlessly?

I've read all the articles on them, but I am looking for someone with a little hands-on experience with one...

SteyrAUG has a couple threads on it. In the HK forum here.

I've heard they started out bad, but are now pretty good. Worked the kinks out of them, and now have two versions. The PTR-91 (thin handguard, french rear site, metal lower) and the PTR-91A1 (HK thick handguard, bipod, HK rear sight, plastic lower with pictogram).

SteyrAUG is the guy to talk to, though.

I have one, Muggzie.

I like it pretty good!  It works best with Surplus ammo.  Federal's brass gets too high pressure in mine.  It will eject it but I quit shooting Federal after a blown primer.

I got about a two and a half inch group out of mine at 100 yards.  My only gripe is that it shoots about 6 inches high with the rear sight completely lowered.  I might try to releive the bottom of the sight to attempt to get it zeroed.

Finish it excellent.  trigger pack has some play.  they were sticking little rubber pads on the pack to solid it up but I think mine is almost gone.

My trigger has a lot of creep, but I'm not considering modifications.

The furniture is crappy, but I haven't replaced it yet.