I am disappointed in that I have not heard that the new Surface RT 2 would support stylus ...
On the Pro (and Pro 2), the stylus is detected separately from the touch. This means that you can do different things with the stylus and the fingers. There are also ways in which touch and pen can be used together to do things that you couldn't do before.
But for this to take off, it needs to be implemented all throughout the line, or developers will only cater to the lowest common denominator.