DAVE definitely doesn't work under PB. It semi-locks up Classic so that you can't run any apps.
Samba would be great, if it worked so that Classic apps could access the shares.
With Sharity's demo, I can access most (but not all) of my shares at work with the OS X side, but not Classic at all, they don't appear anywhere.
This is going to be a big deal, because I'm sure there are a lot more people like myself that collaborate in an all-Windows based office and will need this access. For me, it makes it so that I can't actually do any useful work yet in OS X.