I went through some of the same quandaries when I decided that I needed an AR-15. I knew nothing about them, had never shot one, and didn't even know what to look for.
I had just about decided on a Smith when my son-in-law asked me to help mount a sight on his AR. That got me the chance to take one apart and look at it. I used the various parts listings on the net to figure out how it worked and in doing that I decided to build my own.
I have no idea whether a Smith is better than an Armalite or a Colt or whatever, but I know that with little effort I came up with an AR that goes bang ever time, puts holes pretty close to where I intended to put'em, and - most importantly - puts them very close together if I use the sandbags at the range.
I'm an old guy, too (think 70) and I grew up with Marlins, Winchesters and Savages. I carried pistols for 36 years, and I was pretty good with taking care of them and keeping them working right so I had some very basic skills. If you lay all of the parts for an AR out in front of you and make sure that everything fits together smoothly (buy a couple of fine smoothing stones) and use some logic, an AR can easily be assembled in an hour or two. The only fiddly part is getting the gas block on right and getting the barrel tight. I got what I thought was some very good advice. I was told to buy a quality barrel from a known manufacturer. I looked at Ranier, Green Mountain, Daniel Defense, Anderson, and finally at Faxon. I know there are others out there that are better and a lot of them are more expensive. I made my choice based on the helpfulness of the customer service guys. But mostly all of them were pleasant to deal with. After the barrel, I picked the best Bolt carrier group I could afford. Then I spent a bunch of time making sure that everything fit together smoothly. I picked the carbine length for everything because It appears to me that it may well be the least finicky with cycling everything. I'm told that it also has the worst recoil kick. If it is, it isn't at all bad. You can really get hung up looking at trigger groups. I wound up using a plain old stainless steel mi--spec type from Anderson. I spent a little time with it smoothing and polishing it and it works pretty darn well. You can buy the $200 variety later on down the road and change triggers in 15 minutes. I made a couple of booboos (ya can't put a mil-spec stock on a commercial buffer tube) but I learned from them -- nothing major. I held my breath for a good long while before I pinned the A2 sight onto the barrel -- I'd advise using the set-screw kind for people like me -- but I got it right and its solid.
My rifle is pretty basic, nothing from outer space hanging off of it, but it has sent over a thousand rounds down the range and has NEVER yet had a hiccup. I spent $554. You can find "deals" all the time if you are not in a hurry.
I had a heck of a lot of fun picking parts and building the gun, and I know every little piece of it very well.
Building is a good exercise in my opinion.
