Well, I couldn´t resist to build a custom rig for my character.
But then I ran into too many problems (mirroring anything can screw you big time) and had to backtrack so many times, that I went back to CAT.
Even though people say its buggy, I haven´t really encountered any major bugs with it yet and its still very fast to set up.
So far I customized the basic rig with a bouncy belly, breathing, fleshy eyes, extra jaw controls and controls for the tongue.
I also took the freedom and added some custom controls. If you right click on a CAT bone, you can select "add gizmo" and then chose from some basic gizmos to control the bones.
I just found them to be a bit to basic for my taste. Fortunately you can easily add your own gizmos, by opening the file Gizmos.max, wich is located in C:\Users\yourusername\AppData\Local\Autodesk\3dsMax\2012 - 64bit\enu\plugcfg\CAT\Gizmos
There you can simply add any gizmo you´d like and after saving the file and restarting you can then chose it from the gizmo list.
And of course you can simple put an edit spline or edit poly modifier on top of the gizmo, and move it around using "affect object only" in the hierarchy panel.
I still need to set up more facial controls and build a GUI for them (probably also have to create a couple more morphtargets) and so far I have only done some quick initial skinning.
Here is a quick preview for the fleshy eye rig:
And here´s the belly bounce:
And here some fun with the jaw-and tongue-controls: