I've got one I used on an SBR build, no complaints here besides maybe the laser engraving not staying as white as it used to be :???:, but function wise, and other finish wise, no worries at all. They also seem to fit uppers a bit tighter than some others I have used, but to me is a good thing because I don't like a sloppy fit. Good to go I would say.
Spike or Angela are both great to do business with. A big thumbs up for both of them and their product.