Very informative article. Thanks for the info.
I just played with the Surface Pro Pen... on my Note 2. LOL. All the display models in the Microsoft store I was in were filled with people trying it. I saw the pen open and lying around with no one using it, so figured what the heck. Tried it and found it okay on the Note 2. Even more impressed when I used it's push button top as an eraser. Saw the price was $10 cheaper than the official S-Pen with eraser (or OEM S-Pen for that matter) and decided to buy it (the pen, not the Surface Pro).
I said it was okay on the Note 2 because of a slight calibration issue. The pen has to be perpendicular to the screen to be spot on accurate. If it's held at an angle, the 'cursor' will be a mm or two off and under the actual tip of the pen. Funny thing is, on the Note 10.1, it has no real calibration issue. It is pretty accurate even at an angle.