I incorporated one of their 16" pencil barrels with a midlength gas system into one of my previous lightweight builds...pretty awesome for the money. I was satisfied.
I have a complete upper with chrome BCG. Only problem I had was one of the bolts holding the gas key onto the bolt carrier sheared off somehow. Replaced both bolts and no issues since.
I have one that I assembled from a kit. It was a basic rifle with lightweight barrel. I ordered one of the kits that came with everything but a stripped lower. Soon after unpacking it, I noticed the front site/gas block was canted slightly. I called the company, and they seemed a little disbelieving when I described it, but replaced it. I did pay for return shipping to them. I didn't think to ask when I got my RMA if they'd cover it, and they didn't offer. It's been flawless ever since, but I really don't shoot it much.