I have one! I came across one at Barnes & Noble tonight, couldn't resist. It's the cheapest place around here to get Doctor Who stuff anyways, $24.95 per screwdriver (Amazon's price is $29.99, and Newbury Comics overcharges at $33-34.
Definitely an improvement over the 11th Doctor's screwdriver.
Please excuse the bad lighting, I was shooting with my iPhone.
The packaging:
The battery panel/compartment is now right on the side of the screwdriver, no extending the screwdriver and pulling apart to get at it:
The 11th Doctor's Screwdriver (DS) on top, 12th on the bottom. As you can see, very similar in looks. There's no lower (lights/FX) button on the 12th DS anymore. The black section on the 11th DS is noticeable shinier, the black on the 12th DS is very matte.
Remember how the activation button on the 11th DS is visible after extending the screwdriver? Not on the 12th DS!
Very easy to activate: just have a finger on either side (thumb and index is all you need). The sound chip is noticeable quieter in the 12th DS though.
Being able to activate the screwdriver from the black handle extended or closed means they nixed that big red button on the bottom and the flmsy flip cap (yay!). What is there instead is the removable power core. Bit of a gimmick, sure, but better than the red button.