I think it's all due to the brilliant reputation system...
-just kidding. More likely it's the smilies.
As for our preparedness -- I haven't seen any major problems. Postcounts are up a bit, but spam isn't out of control or anything.
There are lots of things we can do now that we've swapped platforms. Things are just now getting settled down and debugged so I haven't really had time to get into too much just yet.
Little add-ons like the chatbox and the arcade were me figuring out how modifications work as much as anything. Some of them are easier than others.
But yes, we're completely vBulletin now -- much to my delight. Nothing against phpbb, I'm sure it works fine for lots of folks -- but I hate it. A lot.