Rereading the op.
If this is gonna be a truck gun, I'd probably run an aimpoint, with a fixed mount. it may get thrown around / banged up a bit, so being nigh indestructible and being able to leave the unit on for 4 years is a deciding factor to me.
Assumption is the mother of all ****ups.
Know what you know, Know what you don't know. -Paul Pedzolt
"Jack of all trades, master of none, though oftentimes better than master of one" -Mynshul