Well, I have a Spike's Punisher lower and plan on buying a rifle kit from FBT. I'd prolly just get different calibers since I just noticed that you can get one that can shoot the 7.62x39. I'm just curious what people's opinions were on the different brands.
You may want to do more research before getting into 7.62x39 in an AR; there have been quite a few reports of problems with feeding, firing, and ejection of that caliber in an AR. I had two such builds, and I'd have an occasional FTE in both - perhaps 1 in 50 or 75 rounds. Nothing major if you're just plinking at the range, but if you're in a timed competition or worse yet, defending your home, you may not want to deal with that. Stick to AK's with that caliber is my humble suggestion.