iPad air or iPad mini with Retina display

Welcome to the Apple Community.

You could solve your problem by getting both of them.

TheDiamondMinecart wrote:

Shall I get iPad air or iPad Mini with Retina display?

Yes.

It depends on your needs. If you need a very small but capable device that you can take with you everywhere, then the Mini is the better choice. If you need a big display and you want to use productivity apps, then the Air is the better choice. Don't forget also that the Air has a better screen, offering SRGB, something that the Mini unfortunately doesn't have (lower gamut).