Re: Starting my first AR build soon...
I'm a cheap builder (spend as little as possible most of the time).
I've used DPMS, YHM, S&W and Spike's Tactical and haven't seen a difference in them so far. If you do some research (ar15.com has a lot of info on who actually makes parts for most of the different AR15 parts vendors - but there may other good AR oriented forums besides this one but this is the only one I frequent).
Its fun. I'm trying to shake the habit. I'm finishing up one right now (spike's tactical lower, CAA collapsable stock, BCM flat top upper and one of the new ion bond bolts, yeah, so much for the cheaper statement, huh, RRA chrome lined lightweight barrel with mid-length gas system and RRA free float tube.
Without the loaded magazine and the optics (iron sights only at this point) it weighs in at 6 lbs., which is what I was looking for this time, light and easy to carry/handle. I've got the 24" bull barreled bipod free floated varmint rifle version, the 20" HBAR free float flat top A2 version, the CAR15 version, etc. but I wanted a 16" barreled .223 to play with. If it doesn't work out I'll try something else.
Good luck on your build and have fun