From what I've read, all LPK parts are made by just a few companies, but its the end manufacturer who mills them to their specs. DD is pretty much the only one who makes them in-house 100% start-to-finish. Bushmaster used to provide Burst-FCG's to the military, but I don't know if they still do after the Cerberus/Freedom Group merger.
From my experience, DPMS LPK with the blackpaper inside clamshell packaging is the only LPK where the trigger pin doesnt want to walk out whatsoever. The trigger is decent, but I can see how some call it a little mushy. I'd describe it as a steady incline with a small plateau before break ~6lbs.
LMT triggers feel like a glass rod breaking at ~7-8lbs and its hard to guess when its gonna snap. Reset is quick and trigger travel is short for both initial break and follow-ups.
I've been extremely disappointed with the Stag Arms LPK I received in the last 2 weeks. You can see my thread about it here http://www.ar15.com/forums/t_3_118/697456_Testament_to_Stag_Arms_LPK_Quality.html