I bought my wife the full size iPad. You can "split" the keyboard to pull it toward the outsides of the screen, with a break in the middle. Oddly enough, I can hold the thing and then use my thumbs to type on the keyboard when it's split this way, despite my small hands and the relatively large iPad. It's been more comfortable to me than any previous iPhone/iPod/Kindle device I have used.
If the OP has typing as a major concern, it would be worth going and holding them to try this out. As Dennis mentions, it can greatly affect the usability.
If you can spare the extra coin and the extra size, the (non-mini) iPad has faster processors and the larger retina display is nice. I would still take the iPad Mini over the Kindle though.
