Not my cup-o-tea but INGOer MarioMarietta raves about them.
Doublestar makes great AR's and AR products. They also own J&T distributing and ACE stocks. Doublestar is also a military contractor for parts and accessories that they produce, for all 4 branches. They also manufacture the m4 stock that you find on many of the popular AR brands (Rock River, Stag, etc.) The reason Mario is such a big fan is because he works for the family, and has seen their quality control first hand. I have a billet lower in my safe just waiting to be built.