There's a really interesting video here, which is about current research into doing some of the things MS envisions:
TED: Talks Pattie Maes & Pranav Mistry: Unveiling the "Sixth Sense," game-changing wearable tech
I think it's difficult to say that one type of interface interaction is better than another - it not only depends on the situation, but also one the person. SOme are more comfortable with tactile interaction, while others prefer to use words.