Ha, that's an awesome model! I'm gonna take it to Mordor right away.
Well, the HDK we have has got an old display and old lenses so i'd say that the visual display on that is like something between the DK1 and DK2.
The software stack has improved intensly since summer and now sports a good camera based tracking routine. The IMU and the sensor fusion routines are now much better than 6 months ago which is interesting.
We will continue exploring the OSVR ecosystem since it has quite a large gathering.