Not looking for cheap. I tend to keep what I buy forever. If I were to sum up my preferences, I would say I own a lot of H&Ks. I generally prefer .308, but I want to try an AR15 before I go AR10. I try to cover most calibers in my stock pile. I'm open to a custom build, but I'm leaning towards a Colt LE6920socom first. Probably reading too much AR15.com. Maybe a Daniel defense, or a POF. I'd buy an RRA, but I'm scared I'll regret compatibility later. M4s have appeal. Length? Help lead me down the path to a good decision that I'll be comfortable with 10 years from now and 3 AR15s later.