They are cool and everything they make is good.
I had a CAV-15 MK. II and it was great but does not suit my purposes now.
That AR (now Nil8r's) also had Cavalry Arms furniture, which was good. So, excepting their collapsible stock I have owned and had first hand experience with all of their products.
PHX COBRA and I also attended their Introduction to Practical Multi-Gun Shooting course which was cool.