Back in 2012 Google acquired Quickoffice and this purchased allowed for one of the highlights of the I/O keynote address, that is, bringing native Office editing to its Google Docs cloud service. Additionally Google Drive for Work is being sold at $10 a month, and provides unlimited storage capabilities (the timing of Microsoft's Office 365 storage increase was no coincidence).
It is clear that Google is making a significant and strategic play on Microsoft’s core enterprise business, this strategy is perfectly sound but I am fascinated how the marketing department feel about the idea of using compatibility with a rival as a selling point. Surely that immediately labels you as the “other” and any discussion about your service is ultimately never on your own terms. Those guys are smarter than me I am sure they will figure it out, but core identity is a tricky thing and inherently positioning your self in the shadow of an already dominant product is a losing proposition IMHO.