Physically, the Canon PowerShot G12 is almost identical to the G11.
Though a few ounces lighter than the G11, the G12 remains the largest camera in its class. Its design is almost identical to the G11's, including the usable optical viewfinder and large, easy-to-turn dials.
Wow. Looking back, I realized I've been complaining about the G series' controller, a four-way switch plus Set/Function button, for the past three generations. So this will be four: I love the scroll wheel, but find I tend to accidentally hit one of the Manual focus, macro, self-timer, or flash switches when I'm trying to press the middle button. As for the wheel, I frequently press one of the switches while I'm scrolling as well. It's especially difficult to control in cold weather with numb fingers (why am I always testing this camera in winter?)
In addition to giving the camera a retro feel, the dials on the G12 are, for the most part, practical and much faster to use than even direct-access buttons, which always require at least some navigation. Movie mode is new on the G12; having it on the mode dial is always a pain, and there's no discrete record button. But the video recording is pretty limited anyway.
If you like this type of control panel interface, you're out of luck unless you're OK shooting in Program mode. You only have access to this in Canon's Quick Shot mode, a semiautomatic program mode that activates continuous autofocus and face detection.
I'm a big fan of digital levels in cameras, and the G12's implementation is one of the more usable ones. When you hit the level area, the white indicator turns green and expands a bit, making it easy to see so you don't overshoot.