I have to say BCM has begun to dominate the battle market rifle. They are one of the better/best reasobably price AR's on the market. They are one I would take if I needed to bet my life on a rifle.
I just finished building a lower and I am saving my pennies for a nice upper.
The real bonus to build your own is less of saving money and more of getting what you want in the first place and thats where any savings come in. I have the advantage of having run through several different evloutions of Ar and accessories and on this build I know what I like and what I don't.
I have all the lower components that I want. I am leaning towards a LaRue upper. I'll need to save some more pennies.