pick and choose you really can't go wrong.
biggest thing: look for someone who offers lifetime warranty. i.e. RRA, Anvil Arms
I have a RRA, 2 spikes, a doublestar, 3 anvil arms (soon to be 3 more) and they are all very good quality.
I have heard and actually seen a few problems with Superior arms lower receivers if you are looking at doing a build.
Another good one for a great price is Del-ton
Talk with alan at machine gun tours. He usually has sabre defense as well. I don't know much about these but have never heard a bad thing about them. Support the local guys if you can![]()