Your suggestion sounds better to me. I've heard of the upgrade process taking a long time on some big forums.
I think it'll be a case of saying "what new features does vb3 offer that you don't already have?" You've got a very successful forum here and it's one of the biggest vbulletin insalls (certainly in terms of users online). If it aint broke...
Kudos on the new homepage. I've only just noticed it. I like it

There's a version of one of these homepage "portals" for vb3 available at vbulletin.nl. It's called vb advanced homepage or something similar, So at least that's one less thing to worry about if you do upgrade.
Darren.