I spent yesterday afternoon going through the Max CAT rigging videos which are located in 3DsMax help. I feel pretty comfortable in my understanding of the basics, so now I'm going to try and do a couple of short exercises to reinforce what I've learned.
Here are some stills of what I ended up with from the tutorials (alas, I cannot take credit for teapot head or crocodile-lizard, I was simply following along with the video.)
Today I started to work on rebuilding the English Dragon default rig from scratch (this being the rig that I worked with last post) to see if I could address some of the shortcomings I noted. This isn't final, just where I ended up so far - I made a separate head, so that it can rotate without moving the entire neck, used 2 sets of arms instead of legs since I think so far I'm a little happier with the way they are structured, and for right now I'm trying to use a series of spines instead of a long chain of bones for the tail (so that it can be controlled in segments, instead of having to work with each bone individually) - this still isn't working so well, since now it's creating kinks in the tail. I'll post later with some more progress.
Overall, I'm really happy with CAT. It's a very quick way to set up something pretty cool, and it seems really easy to use - I'm just concerned that it may be difficult to get subtle animation out of CAT rigs (I find that Biped has a similar issue). Also I suspect that it won't work well in combination with bones (for example, if I try to use bones to control the tail better) - but I won't know until I try! Also I think the documentation is excellent and easy to follow.