These bits from Engadget sum the most important elements up for me.
"In practice, the resolution is sharp but the field of view is extremely limited. There's a rectangular area in the center of your vision that acts as your "window" into the reality HoloLens presents. It's this limitation that makes HoloLens not a VR headset, and also keeps it from being the Back to the Future 2 glasses we're all waiting for (I'm waiting for that, anyway). "
"The bigger issue for me was that the image was relatively transparent, which often made things look less than real."
"Tracking -- which is to say, "how the headset interprets where your head is in relation to the world around you" -- felt the most fully-baked of any of the headset's sensors. Though the prototype was a bit finicky to move very quickly in, I had no issue turning around quickly or kneeling, or any other movements I tried."
( http://www.engadget.com/2015/0... )