I have been buying kits from Model 1 for years now. When I've gotten a kit from them, there are sometimes minor problems. An example would be my most recent rifle, which did not have he gas port drill all the way through. I fixed it myself with my drill press and a set of hammer and punches in about 30min. Its not a common thing to have that sort of problem with them, but it does happen from time to time. I would say I've used about 10 or so of their kits over the past 5 years. I have also watched their quality continually improve. The only consistant problem I've ever had was the firing pin retaining pin is not very good, and bends after only a few thousand rounds. Small detail though.
I love Model 1. I always order something special, never just a "normal" kit, and they are always very accommodating. Their customer service is among the best I've dealt with from any company in any industry. My registered autosear lives in an Oly receiver attached to a Model 1 kit, and has had well over 20,000 rounds fired, with no malfunctions that were the the kits fault (I've had a few bad mags or ammo, that about it)
I built an 14.5" m4 kit from them with welded phantom (to make it 16") SOPMOD on a rockriver lower, and if someone wants to tell me how to post pics, I'd be glad to show her off. They are a good kit maker. I highly recommend them.