Started at 7:30 (I'd pre-installed XF on a new folder the day before, imported the theme and imported the forums), I moved all of the VB4 files into a new folder, moved all of the XF files I'd installed to root, then had to restart the server as all I got was a white screen.
Then the importing took place:
2m+ posts in 7 hours isn't too bad
Once complete, and it was rebuilding indexes, I started working through the permissions (the test permission tool on XF is amazing), installing needed plugins, and manually re-adding the user upgrades (paid subs).
It took an age, but well worth it, SO much faster than VB4 ever was, and no moaning (so far, users can be a funny bunch, not liking change etc...)
A big thanks to everyone on here who has taken the time to help others and create plugins, the support so far has been fantastic.
Very happy to be running XenForo live