I've had my GN for 5 days now, just upgraded form the OG D1. There are A LOT of pros (too much to list) but here are a couple of cons:
1. The screen is huge! I do love it, it's just a little hard to text with one hand.
2. I randomly lost service a couple times today (never happened with my D1)
3. While in a call, when I put the phone up to my ear while the keypad is displayed, it pushes the keypad, which makes it hard checking voice mails.
4. The battery life is not very good. I loose about 20% over night idling, and almost dead by the end of the work day. Waiting for my extended battery.
Other than that, I love the screen, the camera, the fact that is was unlocked and rooted in about 5 minutes, and on and on.......can't wait for the stable ROMs to start coming!!