not sure about speed but the contact manager is a god send for me as I need to do a lot of work in groups. The previous version contact manager was too awkward to use.
Works in firefox for me, but doesn't work in ie in any of the systems in our office.
The interface looks cooler with a few subtle changes, but you didn't need a new version for that. Not sure about the multimessenger thing though.
on second thoughts, none of the ies are 7, all are six. Maybe they work in ie7