I have the original Jot Pro, and love it. I use it continually with Sketchbook Pro and Flipbook HD. However, I would not use it without a screen protector on, since it has left many scratches on the protector. I'm fairly certain it would cause some minor scratching on the glass (as many have claimed). It seems logical though that this new design would be less likely to scratch.
The original Jot Pro is quite noisy, but as someone that uses it for illustration, I have never been bothered by it. The one thing I hope they revised is the plastic disc. The edges on mine are quite sharp, and should have been beveled a lot better on my Jot Pro version 1.