I just received my Model 1 Sales upper (20 inch A2, heavy barrel) yesterday, and brought it to an indoor range this evening.
It is great! I put about 400 rounds of Federal Bulk Pack and CCI blazers through it, with no FTEs or FTFs other than caused by ammo (a couple of dud rounds). All rounds had a good clean strike on them. The Black Dog Mags fed perfectly, no jams or other problems.
Overall, very nice setup. I am pleased that it worked so smoothly out of the box. I didn't test it for accuracy as I was just shooting offhand at 25 yards, but it looks like it will shoot pretty decently.
Overall fit and finish on the upper was pretty good. It looks and feels like a standard A2 HBAR upper.
Thanks Model1 Sales
Edit to add: I am waiting on a Spikes Tactical 22LR conversion kit for my A3 standard upper, I am sure that will be just as good.
Pics added (excuse the cellphone quality):
http://i295.photobucket.com/albums/mm138/wellfedirishman/ar-22/ar-1.jpg
http://i295.photobucket.com/albums/mm138/wellfedirishman/ar-22/ar-2.jpg
And yes, those are TEN round magazines, since this is California