Due to some excellent weather in the UK, its been an out-and-about last few days, but when I have come back indoors, people are still searching for "iPad vs NGP." Can I ask why? The iPad (even in its second iteration) is a general purpose device, it has touchscreen and tilt controls.
The NGP is a gaming thoroughbred, with tilt, touch (front and rear), analog and digital controls. You can play any game under the sun on it. The only thing I'm slightly envious about the iPad 2 is its HDMI-out connector, which I really hope Sony will pack in there somehow.
If you want to play games as they are meant to be played, you get an NGP, if you want to do some gaming as well as the whole app thing you get an iPad, its quite simple and doesn't require seaching about in Google for an answer.