If you haven't noticed, when your profile was switched to the new forum, the sig file was likely messed up. It changed the forum code  tags to html <> tags. Just go to the UserCP tab and click on "edit signature" on the left menu.
There may be other bugs as well. I'm not sure. But it would be a good idea to check out your sig settings and make sure everything is the way you want it.
Someone also mentioned that their default PM settings did not transfer. You may want to check that out as well.