One of the plusses of my GN7 is how easy it is to hold in one hand. Its width is 120 mm.
The iPad mini's width is stated to be 134.7 mm, so that is nearly 15mm wider, or ~0.6 inches wider.
As I stated in another post, the mini is roughly the same width as a standard DVD case (there are many different types of DVD cases, but the typical keeper case is 135mm wide). Here is an image.
And the side bezel is very narrow. This may be a two-handed device to use in complete comfort. Apple appears to have designed it to holding vertically, too. It might have been smarter to design for landscape holding, which is how I hold my tablets most of the time. Something to think about.