I'm not any kind of expert here, but I will try to answer a few. I'm sure I'll get corrected if I am wrong here but I figure you need a response from SOMEBODY!
I believe the magazines are more affordable for metric and there may be other advantages as well. As far as I know metric is the route most people go. I think the inch is a L1A1 or something.......
Also, it's not about pre or post ban. You can get an FAL now with preban/no ban features, however I believe FAL's are still regulated by the 1989 import ban which requires a certain US part count (7?) to be complaint with the law.
As to makers, I do believe you will hear alot of reccomendation for DSA. It is my understanding they make the best FAL type weapon out. I'm sure you'll hear alot of people say avoid CAI. There's alot of makers out there, so it's just going to depend what you want to spend. You may also check out azex arms. Don't know the addy, but do a search it should come right up. I have heard wondefful things about his builds.
That should get you through til someone who knows what the hell they are talking about comes along. You can also click "the armory" button and I think there's an entire section of the site for FALs where you can probably get more responses.