English is actually my third language, so, I apologize for my "accent". That said, here's my view:
We've been using CAT since a while, and I agree, there are bugs everywhere.
Animators in my team prefers to work with CAT instead of CS, ant that's the main reason why we've switched. As TD and rigger of my team, I had to deal with it, and it seems that we've getting to a point where is not that bad, and we're learning the hard way what workflows to avoid to keep things from explode. It's kinda driving me crazy, but what the F@!!, I like challenges!
I've noticed that a lot of plugins makes CAT even more unstable. e.g.: if you have phoenix FD installed (the fire simulator from Chaos Group) it makes that you can't change the number of fingers of a CAT rig. Weird, but true. Chaos group is aware of the bug, but they say that is a CAT issue. Another example; nVidia physX makes impossible to mirror a bone of a CAT rig, unless you kill all callbacks installed by the plugin. It seems to be a physX issue, but the problem is still there.
I have Max2010 and 2011 64bits in my workstation (recently switched from XP-64 to W7-64). I've noticed that CAT is a little more stable in the 2011 version.
Since I have a couple of plugins including the two mentioned before, I've decided to install a fresh Max2011 32 bits to give it a try. No dual boot, it runs on W7-64. That worked fine for me. Since then, I can use the CatMotion dialog without crashing, mirroring bones is not a problem, adding extra bones to a rig works just fine, and doing some "dangerous" things, like assigning different controllers to parts of the rigs seems to work fine until now. And I had a nice surprise finding that I can mirror CAT muscle strands, that I've never been able to do in Max64. Using CAT muscles is a little more tricky, but I'm using it in some cases.
I remember the first days of CS, and it was bugged as hell, but no that much as CAT though. I'm giving a chance to CAT, and I'm hoping that people at Autodesk will fix is, because it's waaaay better than CS for animators and riggers.
So the answer is yes; CAT is way more stable in Max 32 bits, and there's no need to use a 32 bits version of windows, at least in my case.
cheers, I hope it helps.
M