ok, I'm the new guy.  Debating to purchase complete or build my own ?  Suggestions on what lower to purchase ? Better to buy complete lower or build it up myself ?

I used an Eagle Arms lower, and had absolutely no problems.  Built it using an RRA upper, RRA lower part kit, and RRA A2 stock.  Basically, my entire AR is RRA except for the lower.  

I have heard a lot of people say good things about the J&T kits www. jtdistributing.com.  I was going to go with a J&T, but got such a good deal on the RRA upper on ebay that I couldn't pass it up!  

If you are a "do it yourself" person who gets a lot of enjoyment out of having something you built yourself, then building is a great option.  I know a lot more about the function of the AR as a result of building, and was able to get it together without a problem in one evening using instructions printed from this site.

You will really enjoy building your own.

A lot of folks seem to be going for the MEGA lowers over in the EE. For $89 shipped I can't blame them.