Since the advent of the T-1 Micro, I deemed fixed BUIS obsolete.
I've seen more irons fail than T-1s, big Aimpoints, or ACOGs. It took me years to finally realize that a BUIS will come loose, bend, or break before an Aimpoint in a good mount. That's just how it is.
In those years it took me to realize that, my vision slipped and irons are not quite as useful for me anymore.
I ditched all my fixed irons and now have KAC flips with a T-1 Micro in a DD mount. An X300U at 12:00 in front of a folded KAC front is the best setup I've found as far as absolute durability and ergos go. There is NO disadvantage to running a light at 12:00 if you can.
http://i851.photobucket.com/albums/a...ps97a024f2.jpg