Hi Richard,
I'm a new member to this forum, but have some experience with ARs, and am a member at AR15.com. Really, any of the choices would be good. Besides the ones you listed, there are also Hesse, American Spirit Arms and DPMS. These are also very good rifles. For what its worth, those on AR15.com have had quite a few complaints about length of time to get a rifle that is ordered from BM, and Oly especially. Quite a few people have stated waits of 8 weeks or more. A lot of them are saying to buy whichever you like that a dealer has in stock. Some of the complaints about different brands of rifles are that Colt uses some off size pins, and has switched to using some plastic parts(buttplate door hinge, part of buffer assembly) and BM has had some problems with overtorqueing barrel ass. causing major windage adjustments to zero rifle. Can't recall seeing anything but praise for Armalit, DPMS, and Hesse. Recommend going to AR15.com and checking out the boards.
bergie