He has turned out some bad parts, BUT he has fixed all the problems from everyone I have talk to. He is **** for comms, hard to get a hold of. He also doesnt have a SOT so he cant test f/a guns unles he runs across the border.
I posted about my experience, and I know about 4 other guys that had problems, but they were all fixed but they had to deal with slow comms.
I personally think they are better than the MM guns, but then again I've seen a a drawer full of bad MM parts and bondo finishing.
If you do decide to go with him source your own accessories (bipod/nutsack/etc) and low down payment as the gun will take forever to ship.
BTW you wont get a real BPP vs MM discussion on this forum, as hk21man is very vocal and has the support of the board.