Well, first I haven't tested NFS shares and don't know their useability in classic applications. Which was one initial reason to use netatalk, for allowing older software in classic to access the shares.

Previous to Jaguar, Some of my apps in classic didn't show the mounted volumes that showed up on the OSX desktop. I think it was resolved through Jaguar where I recently noticed the ability for the apps in question to see the volumes.

As for NFS, it is possible and I've heard of people using it. I'd like to try and maintain a consistent way to access the volumes though and have heard NFS and netatalk and Apple's own sharing protocols don't encode all their data in the same way (ie their resource forks and directory data).