Don't go with the leather cases... they shrink over time and the magnets don't line up,causing the display to turn on even with the cover closed. I have learned this from the first gen smart covers. I have both the plastic and leather and the plastic has actually held up a lot better.
http://reviews.cnet.com/8301-31747_7-57608756-243/leather-smart-cases-will-protect-new-ipad-air-ipad-mini/