I'm sure some of us will try importing a vb4 database into a test install using the vb3 importer to see what happens. I thought I read somewhere that the vb3 import will be available with the beta release, and the vb4 one should be ready by the time it's declared stable release/gold.
Actually the only thing that does not work when you import VB4 using VB3 importer is the attachment system.
I really hope this will get sorted very very soon. It's the only thing that keeps me from moving my forums from VB4 to Xenforo.
Somehow the importer works best on Firefox than in Chrome, not sure why but i was getting "duplicate key" errors when importing the users, switched to FF and its about to finish importing the threads and posts...