The latch on the metal cases pretty much blows.
I lost my first 6700 to one of these. Had it on the swivel clip on my belt, tripped on some uneven sidewalk, and the force of me tripping popped open the latch and flung the 6700 out of the case and onto the ground. There goes my screen and the battery flew out too.
The clip kept my case attached to my hip though, so that was nice.
I only use the metal case when I'm going to put the phone in a pocket. I'm using the Seidio leather holster now for when I want the phone on my hip.
I find the metal case prevents crushing and scratching better, but the leather case keeps the phone secured on my hip and absorbs short falls better.