I help support a network of mostly windows clients, but we have a few Macs thrown into the mix as well.
We run a Windows Server 2008 SBS that also hosts Exchange 2007
I recently set up the Mac clients on iMail which supports Outlook Anywhere.
All is well except for one nuisance. Occasionally when a Mac user drafts & then sends an email iMail keeps a copy of the draft even after the message is sent. The message is delivered successfully - so it is not a major issue, just an irritation - but then they have to go & manually delete their drafts. It seems to happen randomly - it will happen on about 1 of every 10 messages or so that are sent out.
I should mention this is with Snow Leopard Clients which (to the best of my knowledge) is required for iMail to support Outlook Anywhere.