As far as I can tell, Mail for Exchange synchronization works fine on my N900 after an OTA PR1.3 update. All my mail folders come across with their contents. My N900 discovers and notifies me of new mail more rapidly than does Outlook on my desktop. The calendar synchronizes fine, and I can accept invitations. I don't appear to have lost any contacts or had contacts merged or unmerged behind my back.

It's disappointing that so many others aren't finding that same level of success.

I'm synchronizing with an Exchange 2007 server. I've no idea if the Exchange/ActiveSync version in use might contribute to the success or failure of MfE in PR1.3, but it seems a possibility.