Should I go with a Rock River receiver or a Bushmaster one.  I am an AK guy so explain as good as you can:)

Rock River.  Only because the quality is just as good on the lower, and they are cheaper.

Is the Rock River upper as good as the BM?

It depends on how much $$$ you want to spend. I think the Rock River Arms lowers are the best value going, the finish is excellent and it is forged. If it's worth the extra money to have the snake (Bushmaster), then go for the bushmaster. If you are trying to build the cheapest priced/good quality AR, go for the Rock River Arms lower. I bought mine from mggunner for $110 shipped. Here's his ad, if interested: www.ar15.com/forums/topic.html?id=71829

Quoted: Is the Rock River upper as good as the BM?

Upper receiver, yes.

Barrels... well it depends.

If you want chrome lined chamber and bore, you gotta go Colt or bushie...  Some say that RRA will chrome line their barrels for a fee, but I aint seen that.