Most of mine are FrankenARs. I have a complete DPMS carbine, one complete LMT, and two complete Colts. I will have a complete DTI (Del-Ton, Inc.) carbine this week. My other seven ARs are all builds that I have spec'd out. I have used LMT, CMMG, and Del-Ton uppers. For lowers, there is Noveske, DPMS, LMT, LCW (LMT), Spikes Tactical, and Centermass. LPK from DPMS, LMT, and RRA. I have made a point to use dependable and well-made products. In the market today, there is a multitude of choices. That goes for buying a complete weapon or parts to build your own. You are correct about the ABC's. There is no real order these days. You pretty much need to check out what is here on ARFCOM. Lots of good info and feedback. Just standby. I am sure that you will get a lot of responses on this thread.