Anybody use a Stag LH upper to do a build? Quality?

I have a buddy who has one.
He honestly cannot say enough good things about this upper.
He's had 1 or 2 issues with it... but stag customer service hooked him with zero hassle and got everything straightened out.

I use a Stag LH NiB bolt in my Sun Devil LH upper, with a "regular" M4 barrel, no problems from it. Not exactly what you're asking about but hopefully relevant enough.