Magic Leap is based on super complex tech that draws images right onto your retina. It's the kind of tech that will take them another couple of years to make small enough to package, and possibly another few years to build the tools to develop for it and to ensure it's not actually blinding people by shining bright lights right into their eye. A friend of mine used it and said Magic Leap, initially, is like trying to breath liquid oxygen in the Abyss: you fight it and can't really take that bright ass light shining in your eye. You have to really get used to it and relax yourself for it to work.
Hololens is just a screen in front of your face. It could never blind you or hurt your eyes. It just works, it works today, it fits in a product form factor today, and after using it for a while, I really don't see much need for an also-ran here. Hololens can do everything Magic Leap is supposed to do, and it can do it a LOT cheaper and safer. Plus, MS dev tools. You just know that Google's Magic Leap dev kit will, basically, be targeted at super intelligent people and require a lot of do it yourself stuff.