Lordgunner: I'm not aware of any states that require a special license to acquire an AR. Certainly not required here in Texas. Other states and even cities might have regulations that may apply. California is certainly not AR-friendly. You might get better advice on this issue if you let us know where you live.
As far as the choices you've listed, I think that DPMS has a better rep than Olympic.
You might want to post your questions on one of the forums dedicated to black rifles. I think
www.ar15.com is one of the bigger and better forums.