I'd go with the Air. I think, which has happened with everyone I know, once you go tablet it's a lot more convent than lugging around a lap top so you'll probably end up using it a lot.
What kind of app you thinking about developing?
From cnet:
What Are You Using It For?
This one's a no-brainer. The joys of lounging around with Netflix significantly decrease when you're spending your time squinting at a smaller screen. But if you're planning to use your new tablet as an on-the-go reader or a glorified email machine that with a beautiful body and a few extra skills, you don't need the same kind of screen.
So if you see yourself doing any decent amount of web-browsing, video-watching, or game-playing, and plan on using your 'pad as a glorified laptop that just moves around your home or apartment, and rarely leaves it, the iPad Air is probably more your speed. But if you're doing more word-readin', and want to do that on the go, the iPad mini might be a better bet. Or, you know, a Kindle or something.
