Well, it's definitely a huge factor as a 15" laptop is still a 15" laptopMore importantly though, currently the Surface replaced not only my iPad and a crappy work Dell laptop, but also added few interesting usage scenarios - I've been taking a lot of hand-written notes on it with the stylus and the touch keyboard is silent and great in meetings.
In my day-to-day, my MBP has basically become what my desktop PC used to be - the big, powerful PC that you use when you need it all. The SP2 has become the small and lean convergence device that can cover most of my needs.
Thanks again! That's extremely interesting. Again, I'll have to pay the Surface some more attention. Even if I never get one, to a tech junkie like myself, it is neat to see new possibilities.