Which is a better keyboard for iPad air? http://www.logitech.com/en-gb/product/keys-to-go-ipad Keys to go is extremely thin and portable, weighing less than 200 grams and 0.24 inches thick. http://www.logitech.com/en-gb/product/illuminated-keyboard-for-mac-ipad-iphone On the other hand, K811 is backlit but is heavier being over 300 grams and is also slightly thicker but is still quite portable. So I guess it's ultra thin, ultra portable vs backlight at expense of some portability and battery life. Has anyone used either of these?