Steven Frank of well known Mac development house "Panic" blogged about the details lost trying to sync contacts through Google instead of MobileMe:
http://stevenf.tumblr.com/post/618349003/here-are-some-thing...
His summary: "If you’re contemplating this change, I highly recommend setting aside a few hours for research first. You may be unpleasantly surprised."
Some more issues are discussed in today's TUAW article, "Sync Wars: Address Book vs. Google Contacts":
http://www.tuaw.com/2010/05/22/address-book-vs-google-contac...
I love Google, and I would probably use it if I had an Android phone. MobileMe's biggest draw for me is its integration with Apple products with syncing and Find my iPhone/iPad.
I'm on an iPhone/iPad/MacBook Pro. The fact that I can't have MobileMe on my domain makes it a deal breaker and Google's offering actually a step above.
"What does can't have MobileMe on my domain" mean?
A number of folks I know use MobileMe to host websites for their domain and handle email for their domain. You do have to "bring your own" DNS.
I have "the same" though Google too, except it's not remotely the same. The contact sync is limited, calendar sync doesn't cut it either without a third party app like BusySync (which I use), IMAP isn't push for real time email, etc.
Also, it's not free through Google, it's ad supported or $50 per year per user.
I have the same through Google and it's free. Apple is losing the cloud race badly, maybe free would help.