Using Dropbox, I can already view all my important files from my iPad and iPhone. Mail allows you to read MS Office documents as well. I haven't yet had the need to edit the MS Office files from my iPad.
I will sign up one day soon, just so I can help my clients with their use of Office 365. But otherwise, I would not spend the $100/year to have an edit capability that I would rarely use.
Have a read of this article that I have 'scooped', which outlines some reasons why you would and perhaps wouldn't subscribe.