hehehee, ok, my physics things really stop after using boxes and spheres, probably the reason I didnt find it all that bad.
Also, my ragdoll was made with ODE, dont have a lot of trouble with that either...
but, from my professional work experience, Havok is not 100% stable either (agree it's alot better though :P).
However, I never had much trouble whatever I did (even in old A6, when i created car physics...).
regards,