Need some opinions/ advice from some of you "gun hands"

There's been so much hype on AR platforms I'm thinking of getting my feet wet, probably a 5.56. What advice do you have on where to buy parts, good buys, just as important, where NOT to, and how to approach doing a lower?

And "how bad" are composite lowers? I have a drill press and Jet mill drill, and consider my milling skills pretty much "beginner." But I do have some measuring tools, etc. No digital scales on the mill

Or is the DIY thing about done, and what price difference between building a decent one and buying a decent solid one used? Many of you know I'm in Idaho so laws are fairly flexible, at least for now.

I'm not interested in a bunch of fancy extras, but with my eyesight I'll need some sort of optical sight, either low power scope or refractor, etc. But I can do that later.