I have had two OSOE Cobra Riggers Belts for around three years. One thing I hate about them is how long the "tail" is after the belt is tightened into place. The excess material really interfered with my gear configuration. I have been using my trusty Galco belts (I deploy with 2) for years.
Here is a picture of the current version I'm using.



One note, it doesn't take 4 layers of SCUBA webbing to hold you pants and gear up.





Like Steve S. said, leather doesn't last as long as nylon. It also tends to stretch out however, the best part about leather is that it conforms to your body.
One thing I've noticed about Cobra buckles, they stick out like a white woman with a black eye. If you are carrying a gun on your belt, why draw more attention to that part of your body?