If you share Office documents with Google Docs, and here’s what can happen:

  1. Critical information in Excel spreadsheet cells disappear. My budget formulas display "ERROR!", and I look like I find second-grade math challenging.
  2. The newsletter I’m pulling together loses its charts, so I’m only updating people with half of the information that parents in the school district care about.
  3. Images are lost on invitations, leaving friends feeling ‘flat’ about the party that we know will be the best Daytona 500 event we’ve ever had!
  4. Turning to my work at the office on a document, tracked changes disappear and the ‘Comments’ are not tied to the sources. The message doesn’t flow, to say the least. My focus and influence are questionable…
  5. I’m updating my bio, getting ready to present at an event. Formatting including tabs, paragraph spacing and page margins move around and some drop off. I look ridiculously unprofessional, and I’ve lost the emphasis and style I’ve just labored over.
  6. Next, I finalize the presentation. My PowerPoint fonts are changed, and animations and transitions are missing. At the event, I lose the attention of customers in delivering it.

Full read: Technet.

Also see:
Compare Microsoft Word Web App vs Google Docs
Microsoft Office Web Apps vs Google Apps - Comparison