I've had my 12 PM for 1 day now and I have already returned 3 cases and have 3 in the mail I'm waiting on. After a lot of debate I decided to go with these:
apple leather - saddle brown
solidsuit
phone rebel clear
ringke onyx - its the only one I actually have and I'm pretty impressed. For $10 it's an amazing case and don't know why anybody wouldn't choose it over the caudabe sheath
The Onyx was the first case I got for my 12 PM, and I love it. But after getting the Sheath, I've barely used the Onyx.
Part of the problem I have with the Onyx is the way it shows the frame of the phone at the top and bottom. Maybe it's intentional since it's pretty much symmetrical, but it just looks sloppy.
I've returned tons of cases for that exact reason. Either they should show the frame all the way around, like the Apple cases, or they shouldn't show it at all, like the Sheath. It took 2 replacements from DBrand to finally get a Grip case that didn't bulge either at the volume bottoms or the power button.
I don't understand why case makers seem to be having so many issues with this new (old) form factor this year. It's like they've forgotten how to make cases for phones that have squared off edges.