If the numbers are right here, then the $ 3/4 million saving for 800 employees as a result of switching to Google Apps is true then this is significant.
Serena Dumping Microsoft Exchange for Google Gmail, The Cloud | eweek
Serena Software expects to save $750,000 per year by shedding Microsoft Exchange Server in favor of Google’s Gmail application for its 800 employees, officials for the Web development software maker told eWEEK Nov. 12.
We posted on this before. I know from personal experience that working with gmail in a browser is exponentially faster and smoother than Exchange in Outlook. The shortcuts, the sync with blackberry [read, archive in one is replicated in the other], the speed, and the capacity [no admin telling you that your 100MB mail file is full] – all this to say the facts and savings will at have some point to get banks interest.
Bankwatch 
I’m always bemused by people’s love for Outlook and Exchange Server. But to each their own: I typically chalk it up to:
1) the need for a client app (which is still possible with Gmail)
2) the reluctance, or perceived lack of benefits, to change.