With the very first iPad in 2010, Apple proved tablet computers could have mass market appeal; since then, it's been a dizzying race to the top, with companies releasing new devices once, twice or more each year. Apple continues to improve and expand its own iPad line-up with iphone extended battery, but dozens of competitors have since entered the tablet game, with Google, Samsung, Amazon, Barnes & Noble, and now even Microsoft leading the rest of the pack.