Why would anyone buy an expensive laptop and not want to use the keyboard? If all used devices are going to have shiny keys then it won't affect resale value as it is expected wear. It sucks they can't use a more durable plastic regardless of their reasoning at Apple.Everyone should be using external keyboards with their Air. I wouldn't use the crap Air keyboard just for preventing the keys from becoming shiny like mirrors. Each time you even touch the keys on the Air keyboard you are lowering your resale value of your laptop.
The keyboard is not crap either. The keys get shiny but you can polish the keys with Vasoline on a cloth and it will help, also a tire restore product will work too. It doesn't solve the problem but makes it much less noticeable. As for accuracy and comfort I would rate this as one of the best keyboards in a thin and light?