I used to use Squeaky wheel.. I'm not sure what it can do that Squishy doesn't.
I really hope squishy gets some filtering soon :) I always get special assignments like specific classes, or 2 groups, plus this other guy... that kind of thing.
I really don't want to hijack the Squishy thread, but I looked over the Squishy feature list and I feel the converse is about equally true. There's some secondary features in each that don't exist in the counterpart. Also, SqueakyWheel does have class based filtering. It's a pretty straightforward configurable priority boost for each class, that I think you should pressure the author into adding into Squishy. I didn't really like adding filters so much as tweaking priorities.
That feature has been the only thing in all of WoW so far that has actually made me write, release, and maintain an AddOn. I really don't enjoy the last two, and there aren't really many other priority based health bars out there. But if you tell the average WoW player to go to SVN in order to grab an AddOn, they aren't going to do it.
I just stumbled across this AddOn today, and it looks great.
I've been reluctantly maintaining SqueakyWheel for the last few months, because no one seems to want to write an emergency monitor replacement. Please release this on a major site so I can start telling people to use Squishy! Also, you might want to poke through its feature list for potential things to do with Squishy.
I did notice that Squishy seems to be more PvE oritented, and SqueakyWheel more PvP.