It might be, but I've been using the rivet on another phone for about 3-4 years now, and it's the most secure clip out there. I explained in another thread (or this one...cannot remember) that if someone tried to pull my phone off my clip, they'd get hurt and thrown to the ground before it would give.
I have a tendency to break the plastic clips or holders due to over-use.
http://web.vajacases.com/ultra/ultra.html
The other thing is I don't want to have to turn the phone a perfect 90* in order to remove it.