I have to admit I'm intrigued by this. The lack of 1080p is disappointing, though if this is mildly successful (and even if it isn't), that will probably come in a later iteration. If $700 is the list price, we could possibly see these discounted significantly after a while. What's cool is that it theoretically eliminates the need to dedicate a large room in your house to being a movie room, and you don't have to deal with the complexities of light control. I'm skeptical of the headphone's bass response, so my initial thought was to combine these with a movie room with 5.1 or better audio, but I'm not sure if that's possible (can you remove the earpieces on these?). Of course, the advantage of the headphones (if they deliver reasonably good surround sound) is that, again, you don't have to have a room dedicated to HT. Three of these and my wife, daughter, and I can just lounge on the couch or in our bed and watch a big screen, light controlled, 3D movie in the middle of the day.
Wearing these things obviously takes away from the community aspect of movie watching but, let's face it, movie watching isn't the most social thing anyway, since no one likes to be distracted by someone else talking during a movie you're trying to watch. And it could be argued that even a conventional setup with 3D shutter glasses isolate you from your couch-neighbors. But for sports or TV watching, where it's more acceptable (or even preferred) to socialize, a more conventional TV/projector setup would be preferred.
Other concerns are the scalability. With my movie room, I can seat six people (and there's room for more, but I only have six theater chairs). With this, I'd have to buy six of them ($4200 total, at list price), to serve the same number of viewers. For just the three of us, $2100 (or, hopefully less, if discounted) could be justifiable if the experience seemed more immersive than what I could get with a 3D projector in that price range, but $4200 would be well outside of my acceptable range.