Basically everything increases by 33% for things like Hit Recovery, Block Rate, Cast Rate, Walk/Run Speed. While transformed you can only do what a druid in wereform could do. So armageddon, summon wolves/bear/vines/spirits. You can cancel the transformation by switching acts or by casting werebear/werewolf.
There is an excellent post over at the amazon basin, however I can't get on their server at the moment to provide a link.
I got a delirium on my kick sin. It's annoying when it triggers but you still can cast town portal and quickely swap acts. While in (maybe out of) shape you're not completely helpless as your character speeds up considerably.