One of my coworkers had an equally bad experience with Netscape Calendar: one day it was just gone. Not only had they cancelled the service, but they'd deleted all the user data. They had been careful not to tell their customers of this plan, because they "didn't want anyone to complain."
I'd been contemplating switching some of my domains over to Google for email -- Dreamhost makes it easy to set that up. Maybe not.
Yeah, almost all of my websites are third-party-hosted now. But the hosts are nothing but a mirror for the various internal working directories. And they're going to stay that way. If I can figure out how to do that with some Google's services, I may consider using a few of them.