Usually for my Mac users, I set them up with a wireless sync tool that allows them to sync directly to their Domino Server with no need for sync software at the client. This way, they can run around with a Treo that's always in Sync and it does not matter if they are PC or Mac based - the beauty of Notes.
I'd like to ask an Notes for Mac users out there if and how they are synching their SmartPhone/PDA with Notes.
I suppose this brings up the bigger point of the need for suitable sync tools between the Mac and not just the Treo but any PDA or SmartPhone. I wonder how long it will be before a major sync tool vendor embraces the Mac to provide quality sync between Lotus Notes on the Mac and any number of mobile devices, e.g. Treo, Palm, Blackberry, etc..