I don't like Granny Smiths myself. Too hard and sour. One bite, and this is what they do to me.

Granny Smiths make great apple juice, but for eating raw delicious, royal gala, macs are much better imo. I find apples easier on my dentition if I slice them first. Then I dip the slices in peanut butter for added nutrition. But I do leave the peel on -- it's the most nutritious part of the apple I've heard.    (I wash 'em carefully, of course).