As a small business owner I strongly disagree that offline access to data is not important. Google fails this. The combination of an Exchange Server + Outlook (or Apple Mail/Calendar/Address Book) is very reassuring. I don't agree with Google's 'Cloud only' approach.
Microsoft Wins.

Mobility : I need/want to be able access my Email/Calendar/Contacts on phones or tablets seamlessly. A hosted exchange account gives me the same convenience as a Gmail account without the privacy issues.

I am growing increasingly concerned about preventing privacy 'leakage'.
Google I have trusted up to now but if given a choice, I strongly favour having my data hosted in the privacy of a personal MS Exchange server rather than being constantly rummaged through by Google algorithms.. The recent push by Google to incorporate Google+ into everything just further alienates me, a former big Gmail user.
Microsoft Wins.

File formats : I hate having my data locked up in proprietary formats but since the corporate & government sectors have long since standardised on Office formats I give in and go with that.
I have waited decades for some one to come up with a compelling successful alternative but it didn't happen. I recently tried Google Drive (Formerly Google Docs). I was _horrified_ to find that when I uploaded a file it was automatically converted to some proprietary Google format that no off-line software in the world could make sense of. No thanks!
Microsoft Wins.

Look I hate the big monopolist Microsoft as much as anyone who is old enough to have witness their rapacious business practices for the last 20 odd years but as far as I am concerned Microsoft have a mature product which is suddenly affordable and accessible to mere mortals whereas Google have a nebulous, ever changing, 'not quite there' product which has questionable privacy.

My 2c.