Google has released a Slides app for iOS, showcasing their new material design. Google recently broke up Drive into multiple mobile apps, and Slides for iOS has long been anticipated. Google now has a competitive offering on iOS, giving Office a run for its money.
Microsoft Office Compatibility
For any customers to switch to Google's offering, their service must be compatible with Office. They know this and are highlighting that you can not only convert Office files, but in the iOS app you can edit Office files directly. This has been the case on Android and on the web for a while.
Wasn't all of this in Google Drive?
Yes. But Google broke apart Google Drive on mobile, giving each functionality its each app - like Office (although Office 2014 bundles everything together, and makes you download everything). It seems to be a better marketing move on Google's part, since now they have apps to match up directly against Office. Further, it brings this functionality in view of their customers; it was easy to assume that Drive was only for storing files.
It also lets users download only apps that they need or want, not the whole suite.
Office v. Docs, Sheets, and Slides
Which is better on iOS? Well, let's not get into a flame war. People are welcome to choose their own preference. But does Google have an edge on iOS?
Apple customers are not heavily reliant on Office, or any Microsoft service really. Office on Macs is clearly sub-par to the Windows 2014 version (aside from OneNote, which is a separate app, but even then Evernote has a large following), SkyDrive is not as integrated into OSX. Google on the other hand has long been catering to iOS as a first-class citizen, sometimes with updates coming to iOS even before Android.
While there are changes happening, like Apple Maps and Siri being powered in partly by Bing, the customers are still more in touch with Google.
Microsoft's Office for iPad may change that, but Google's offering is very attractive OSX and iOS to users that don't see value in buying Office.