I am ecstatic for Google Glass. I can't wait. I'm applying to the developer beta with a few healthcare ideas. The opportunities are endless.
I've been brainstorming ideas for the past few days. What can be commercialized? Will hospitals or physicians pay for it? Will the users appreciate value? Will they feel weird using it? Will the value outweigh the awkwardness of feeling kind of a like a cyborg or android?
The marginal value of Google Glass relative to modern multi-touch smartphones (iPhone, Androids) is that Glass 1) is hands-free 2) excels at providing "at-a-glance" information 3) is always available (not in your pocket). The best applications using Glass will really take advantage of those 3 traits. Apps that don't take advantage of these will be relegated to the underworld of the Glass Play Store (or whatever Google decides to call it).
On the downside, Glass doesn't have robust UI. Unlike a smartphone, tablet, or PC, there's no screen for that you can manipulate. That's severely limiting (on the bright side, Glass is designed to frequently communicate with your smartphone so that you can use it as necessary). Moreover, the small screen that is available in glass can only house a few words, maybe a dozen, as best I can tell from all the videos and journalist previews.
Those that try to take advantage of just one novel feature of Glass, without realizing and fulfilling the dream of a bigger picture of cross-device utilization will fail. The developers that figure out the best interplay between Glass, smartphone, and other major services (web or locally hosted enterprise services) will be the most successful.
Let the races commence.