Jason Snell, writing for Macworld:

Microsoft released new versions of Microsoft Office for the Mac, all based on the Windows code base. The familiar Mac versions of Microsoft’s apps vanished, replaced by programs that didn’t behave like Mac apps at all. They were very clearly members of the Office for Windows suite, ported over to the Mac.

This was a well-known phenomenon, other looks creeping onto the Mac, making an application’s interface feel like it just doesn’t belong.

Jason continues:

Open Google Docs for iOS and you’re whisked into a Material Design world. To create a new document, you must tap a large red circle at the bottom right corner of the screen. The options icon is three vertical dots, rather than the three horizontal dots favored by Apple. Menus display in Material Design style, white cards on a gray background.

And:

A common response to this complaint is that Google is after “consistency.” Material Design allows Google to offer the same interface everywhere, across the Web, Android, and iOS. You know who else defended their choices with that old saw? Yep: Microsoft. It was more important to Microsoft for people to get the same experience with Office when moving from Windows to Mac than it was for Mac users to move to Word from some other Mac app. It was a bad rationale then, and it’s still bad today.

I think Google’s mistake (and Microsoft’s before them) is in designing for themselves, rather then the community they are entering. Either that, or this is a genius move, a shrewd play at making it easier for folks to make the move from iOS to Android.

But if not the latter, design for the community, don’t make it jarring to move from one app to another. You’ll stick out like a sore thumb.