I first reported on this new initiative late last year, and it's now time for an update.
I should note that I have been using Google's productivity tools outside my professional life for many years, and so there is not much of a learning curve. I think this will also be true of some of the more broad population at UMich, but will not be true universally. And I should also note that I had been using a second Gmail account for my professional life too for the past 2-3 years. The main driver for me was storage space. While I'm not a huge fan of Outlook and Exchange, the service operated by ICPSR's parent organization - the Institute for Social Research - was always solid. However, the killer was that the allowable quota for mail was very low (400MB by default), and so I found it frustrating to always be shuffling email off into either the Trash Can or into PST mailboxes. It was especially rough when it came time to search for something.
And so the move from a consumer Gmail account that I use for work to a Google Apps Gmail account that I use for work has been a small change. The change from Exchange to Google Calendar for managing meetings has been a bigger change. On the plus side I'm finding it much easier to manage a single, coherent picture for meeting invitations; I had been trying to manage everything inside of Exchange before. However, I probably receive 100 meeting invitations for every one I generate myself, and so I haven't had to spend much time and effort ensuring that meetings I create on my Google Calendar are ending up on the ISR Exchange server intact. In fact, most of the headaches I experience with calendaring are related to cases where someone generates an invite within the ISR Exchange server, but does not include anything in the "body" of the invite. If I try to "read" the invite on a mobile device (e.g., Safari on an iPad), the meeting invite shows up as an empty message. And so I then track down a "real" computer to see what the meeting invite is all about.
My main take-away so far is that moving from Exchange to Google would best be done (1) quickly, and (2) all at once. My sense is that we early adopters will continue to face a few headaches like above until the rest of the organization moves to Google in 3-6 months.