Well, I'd say the central theme is human connection, and then the question is what you need to make that work.
All I can say is that the iPad's screen seems to be over the hump for this! We have beta testers, and they honestly seem to be doing great. You can see a few tweets they've made at https://twitter.com/understudyapp . You might also be interested in this video of it in use - https://www.youtube.com/watch?v=KrdjKvka558 . If you look at it _statically_, it looks bad, but when you see it in motion, you see that it's effectively gesture.
You're trying to visually communicate and gesture, not create an artifact to refer back to. My handwriting on real physical whiteboards is terrible, but they still work.
It would be interesting to try on an MS Surface. To literally answer your question, (1) there are a lot more iPads out there than Surfaces, (2) I worked at Apple for 7.5 years, on the Cocoa Frameworks for most of it, and I'm very productive in this environment.