Finally got around to getting MT4b2 up and running on the server. It's taken a few days for me to get the plugins copied over from the previous version and all the new default templates restored, but now everything seems to publish and work. I've got it running with a fairly plain default look right now.
There's a lot of stuff in MT4 to wrap my brain around. The default templates have a new structure that give it much more of a programming type feel. Most of the tags look pretty much the same, so I probably could have gone with the templates I'm currently using, but I wanted to start off fresh to check out the new templating structure. It's going to take a while for me to figure out, but it looks pretty cool. Very modular.
Not all the plugins I'm currently using are compatible with MT4, but none of the ones that don't work are vital, so I can wait until new versions come out. I'm really digging the new UI. It has kind of a Vox-y feel to it almost. Lots of new features to investigate and check out.
It's going to be fun to play with. MT4b3 should be coming out soon (tomorrow according to a recent email on the ProNet list). A little more testing and tweaking, and I think I might try switching over to the new version for some bleeding edge testing.