Did you try the new pen on the SP3 or S3? I'm wondering how much that custom chip in the SP4 contributes to the overall experience.Just returned from Best Buy where they had a demo unit on display. I have an SP3 and S3 and love both devices. On the launch day I ordered the new keyboard with fingerprint reader and the pen as daveyp did. Now today I got a chance to touch and feel the whole shebang. I am happy with my choice as the new keyboard feels AMAZING and the pen is great with the way it feels on the screen. (I may need to pull off the glass screen cover it felt so great). The pen definitely has some weight to it which has an excellent feel. Still cannot get over the feeling of the keyboard though.
As far as the SP3 vs 4, I will not need to justify the upgrade as it is not a big enough jump for me to make the upgrade. Yes, it is a bit thinner, but not enough of a difference for me.
Just my 2 cents.
Glad to hear Best Buy has demo units... that will be much more accessible to me.