The good one:

Pitbull is by far the most customizable unit frame addon out there for Cataclysm and you can really make your frames look amazing!

The downside is that it looks like someone puked on the screen by default, and the customization options are not intuitive at all.

There's also an additional plugin for watching absorb shields right on the health bar. very nice!

You'll also notice the version I linked is not the most recent on Curse, this is because the Pitbull devs started making changes for MoP before patch 5.0

TESTED AND WORKING!

KNOWN ISSUES: None