See these videos on some pretty cool features in the just released new version of ArchiCAD. ArchiCAD seams to be BIM leader in teamwork and user management / project access. As well ArchiCAD improves performance with the introduction of 64-bit versions for Windows and soon on Macs too.
These are some of the new ideas:
Workflow through the new BIM Server
BIM Management: Data Safety
BIM Collaboration: Teamwork 2.0