Are you having a Blonde moment.
got a MBP 2010 model.. installed ML today.. not any faster, everything is TINY, can't log into iMessages (says wrong password... its the RIGHT ONE).. cant use herald with ML.. NOT IMPRESSED... epic fail
Sorry to hear you're having trouble. I haven't had the same issues and can't speak to the cause, but it looks as though Herald may have had a release now for Mountain Lion. Hopefully this might help a bit:
http://www.macupdate.com/app/mac/32744/herald/
Andrew