As a backup sight, they are fine. They are actually proved to be tougher than Troy and some other more expensive steel BUIS in some drop/impact testing that I saw.
That being said, I wouldn't want one as a primary sight. The aperture doesn't work for me well and they do flex a little bit.
Troy BUIS are the lowest that I have used, they will normally fit under pretty much any optic that is mounted to the correct height.
Of course, unless you have Quick Disconnect scope base, it is kind of pointless to use BUIS. If you are going to have to use tools to get the optic off, you will have time to put the carry handle back on.
What type of base do you have that requires you to slide it off the back? Are you sure you can't just turn the screws a little farther and take it straight off?
I am no longer participating in gun forums.