I put one together from RRA and have been exceedingly pleased with the results. 600 rounds without a single weapon malfunction, and that's without cleaning or additional lube.
I havn't bagged it up for accuracy, but I think that 2" groups will be easily attainable. RRA usually advertises 1" groups FWIW.
I've never heard of any other finish problems, and I've handled several RRA guns / receivers through my shop. All have been top quality in fit finish and assembly. The only thing they don't offer that Bushmaster does is the solid film lubricant on the inside of the upper receiver. Of coarse, chrome linings are not available on all barrels yet.
I am starting to favor RRA over Bushmaster simply because Bushmaster is starting to price themselves into Colt territory. I still like, own, and sell Bushmasters, but they are getting too proud of their product I think.
Saleen