Overall I think this is great news as last year I bought into the MS ecosystem after 5 years in the Google camp. I was finally fed up with Google's increasing restrictions for their free products (they removed EAS support for iOS, their IMAP implementation has always been problematic, etc) , so the time came to choose to pay either for Google Apps or to go MS. I finally chose Office 365 Small Business Premium, and here's what I got:
1) Email: Hosted Exchange, 50GB per account. It's a great email service, keeps everything sync'ed with EAS across all my devices. Works great with bot iOS and my Mac.
2) OneDrive: 25GB storage included with the Office 365 subscription. Right now it's missing the Mac sync client, but I use it on my work PC and it works well. I use a small tool on the PC to compare and copy the contents of the OneDrive folder into a DropBox folder every 5 minutes and that's how I get the files sync'ed into my home Mac. It's an ugly workaround but it won't be necessary as soon as they release the sync client for Mac (they showed an alpha build at the SharePoint conference earlier this month).
3) Office online: It reads directly from my OneDrive, others can collaborate. Everything gets sync'ed to my work PC (and eventually to the Mac).
4) New iPad apps: I can create standard Office documents on the road which will be waiting for me as soon as I get home or back to the office.
5) Desktop app. licences. An added bonus for me really, as I already had 2011 Mac and my work-provided 2013 copies. Will be nice to receive 2014 automatically on my Mac as soon as it's released though.
For me the though, the most important feature is that every application, no matter the platform, generates standard office docs. (.xlsx, .docx, etc) and in my profession, for better or worse, this is how the world works. It's a huuuge time saver not having to convert every document back and forth as I would have to do with Pages/Google Apps.
All of the above for US$150/year. For me, Office 365 is a great deal.