I'll be all over something like this if/when old age or injuries keep me from riding a normal motorcycle. It sure beats the heck outta those Gold Wing trikes.
Did my test ride on Thursday, and that's exactly what I came away thinking. If some physical condition kept me from riding on two wheels, this would be a great alternative.
I think what this is really going to appeal to are 4 wheel riders that want to take to the highway. It's definitely road worthy, but it seems to handle like a four wheeler. Definitely not a bike.
My motorcycle instincts made me pretty uncomfortable in the corners. You don't countersteer. The centrifugal force really feels like it's going to pull you over.
My instincts also had me grabbing for the front brake, but there isn't one. Only the footbrake which operates a three wheel ABS system. I was talking to an owner after the test ride who said that an aftermarket company makes a hand brake adapter for people like me who think they can't relearn.

I liked the sound of the engine -- 998cc (I think -- it says 990 on the decals) Rotax V-twin. Very peppy, torquey.
Overall evaluation: It's a very fun toy. If I was on vacation and a place nearby was renting them to go see the area, I'd be all over it. As I mentioned above, if there was some reason I couldn't ride two wheels, I'd be all over it -- especially after hearing there are aftermarket bags to put it into a touring configuration. Would I rather be on it than on two wheels? No. Cornering a bike is a lot more fun. They're on to something here, though, and I think they'll sell what they make.