It is big, for sure, but it does run exceptionally well, HD resolution and all.
Nope. S-Pen usage, and all the associated apps, are built in to the framework of TouchWiz. So, unless someone goes to the trouble of extracting them, the pen is nothing more than a pointer. Relating to that, however, if you run your Galaxy Note in "Tablet" mode, by adjusting the DPI, you can use the S-Pen as a mouse. When you hover it over the screen, an actual mouse cursor will appear, and you can do hover gestures on web pages and such, and click items. So, it isn't totally useless.
As for the S-Pen in day to day, I never really use mine. It works pretty well in some games, as the pen is much smaller than a finger, and thus doesn't cover up as much of the screen. To me, though, as I mentioned to sionyboy, it was always just a big, slightly faster GSII with a sweet screen. The stock ICS ROM I'm using for it is excellent, and runs very well, and the S-Pen is hardly missed, personally.