Great company. Ordered a complete upper and shipping did take a couple weeks but they are flooded with orders right now. Would recommend them to anybody!
I wouldn't know why not. I've never done an SBR, but both full uppers I've purchased looked and functioned exactly as expected. Sights, m4 cuts, etc all lined up nicely and worked as expected. Accuracy has been good, reliability has been good, and the price was exceptional.