There have already been reports of a much cheaper (and far less functional) competitor to Google's Project Glass, but this is the first we've seen about a likely real competitor from a major company. Microsoft has filed patent applications for its own version of Project Glass, which was published today.
The big difference between Google's approach and Microsoft's is that Google's Project Glass
is intended to be something you wear all day long, while moving
around the world to get information about things that are nearby, receive notifications, communication, get directions, and more. Microsoft is designing it's product to be something that is worn at live events like concerts and sports games. Microsoft's glasses will beam text and audio overlays relating to what you're watching.
So, maybe calling this a competitor is pushing it a bit. Really, Microsoft's product seems to be a straight augmented reality product that will replace a bit of the functionality that you'd get with a smartphone and a pair of headphones. We'll see what it looks like if/when it's actually released, but so far it's not wowing us all that much.