I just purchased a lightly used LaRue VFZ fixed BUIS because the price was nice, I needed a sight and I am familiar with the level of quality in LaRue products.
However, upon examining and installing the sight I became puzzled about the VFZ mount's utility. Without the QD locking thumb lever that is common to most of LaRue's sights & mounts, a tool is required to uninstall the VFZ sight. All of my other BUISs use either Torx, Allen or flat-heat screws to attach, which therefore also requires a tool to be used to dismount them. But with the VFZ mount there is this extra ~1/2" lump sticking out from the right side of the mount.
If one is going to have to use a tool to dismount the sight, why not just offer a model that uses standard Torx, Allen or flat-heat screws in a traditional "clamp" style mount for a much more streamlined sight? As a bonus, it would likely be cheaper to produce and might therefore now be within reach of more customers with smaller budgets. And introducing more folks to one's product line, especially one filled with soooo many quality items, is never a bad thing.
ETA: While I'm thinking aloud, why QD on BUIS at all? I understand on the optics mount as the sight may go Tango Uniform and need to be vacated RFN. But do BUIS ever need to be dismounted quickly?