DO NOT BUY A BUILT RIFLE!!!
Save money, do it right and build your own! There are plenty of folks here on INGO that can help you build if you want to do it yourself.
I used a MEGA Upper/Lower.... Read the Review... its worth it.
I want another one myself...I can see both sides of the debate. If I were to buy a factory one it would be either an Armalite SASS or a Les Baer. I know they are more expensive than most, but if someone garuntees 1/2 MOA out of a semi-auto, that's pretty hard to beat.
Get the Armalite AR-10, you won't be sorry.
If you really want to spend some coin go ahead with the LMT.