If you're measuring numbers by which singular phone model is the best-selling, the iPhone is still the market leader hands down, but obviously Android as a phone OS has a larger installed base overall. I almost couldn't believe Apple sold 4 million 4S's over the weekend. Just goes to show that people will cry foul about a "minor upgrade", yet turn around and spend their money purely because a new iPhone is a new iPhone. Now that the iPhone is on the 3 largest carriers the real battle between Android and iOS will get started and I think we'll see an explosion of superior Android devices out there. The gloves are off and I for one am excited to see what's coming down the line.