Just word of mouth here as I only own Arsenals. My quick answer is Waffen Works. Interarms used to make good stuff but a lot of people over at AKFiles are having issues as of late (last 6 months). I have only heard a few issues with WW and of that couple I could tell some were more a user issue vs WW issue.
Success is a lousy teacher. It seduces smart people into thinking they can't lose.
Certified Glock Armorer