http://aresarmor.com/store/Item/billet-ar15-80percentI did order and GET an 80% billet receiver from ARE about 10 days ago. Their site shows inventory and claims if it shows inventory..it ships. Took a chance and it took only a few days for the receiver to show up. The machine work appears to be very good quality. The price is a little excessive.
I saw over a dozen receivers in a case at the recent Sioux City gun show. There was something wrong with each of the receivers as far as machine issues...so, the $125 price tag was not worth the problems (errors in pivot/takedown holes. Incorrectly machined bolt release...etc.
Unless you have a milling machine (or access) finishing an 80% will require a drill press and a receiver specific drilling fixture (maybe another $125+). Almost $300 before a usable receiver plus labor is very expensive. It appears some of the parts places are starting to get a few things here and there.
Doing the finish work with a drill press would get the job done...put not particularly pretty and there will be a bit of a learning curve. I have done enough real machine work to understand some skill and experience would help with the drill press route.
Guess what I am saying is...weight your options and know your limitations. I am looking forward to doing my machine work, but I have a few years of experience and my own milling machines. Check out the videos on youtube and ignore the CNC vids unless you have a CNC machine.