clandestine
AR-15 Savant
I don't really know anything about the fixed v. QD debate from personal experience, but for what it's worth, I recall reading in the new edition of Maj. Plaster's tome "Sniper" (great "can" reading) that he had tested many of the most popular QD mounts (without mentioning names), and, while many were close, he had yet to find one that really did "return to zero."
If he did it wasnt a LaRue. Todd Hodnett did the same tests and LaRue had no measured variance compared to premium fixed mounts.