Devl,
When it comes down to it, they're both listed as a "40" To use the word "standard" can be misconstrued for either sight as "standard" is a generic term. When these sights are being talked about off the cuff, back and forth, you almost have to say "A2" or "non-A2" to clearly differentiate which one is in topic.
As far as the TROY goes......if I'm a nimrod and don't know my butt to my elbow about any of these sights and have never owned one, it's less appealing for me to go out on a limb and buy a TROY and "See if it's everything it's cracked up to be". The ARMS is tried and true enough for me. I guess when I have played with this stuff for years (like I observe some of you guys have), and I have a drawer full of duplicate parts, I can then start trying different things to make life more interesting. Right now I just want stuff that I know has worked in Iraq.
Thanks for the help.