I've found the ARMS mount to work itself loose. Maybe it just compresses the receiver over time and gets loose that way. I don't know for sure. It was tight when I first installed it. Not a favorite of mine and I don't like the way it mars, marks, scratches, and might be bending the receiver inward. I think it throws off the accuracy as it moves as well. Plus it's not fun to go to the range with a tight mount and leave with a loose one.
The B&T mount is better because it can just be left on. You still have to be careful installing it with even pressure to all the screws or it can compress the receiver enough hamper bolt movement. I have not ever had one come loose but I don't yet have years of leaving it in place to verify.
I have not used the actual German made claw mount but it probably works well if its service record is any indication.