Tune in an FM radio station? Accept a microSD card? Allow you to swap in a spare battery without special tools? Allow easy access to your data from any computer at any time using a readily-available USB cable? Oh, there's lots of things! Neither is without fault, but Apple has always cheesed me off because they release a product with deliberately limited functionality. You can sometimes unlock these functions via jailbreaking, but that's no better than rooting your droid. You can't expand your memory at all. You bought an 8G iPhone, then realize you'd like to carry around more than 8G of music? Too bad. Wait a couple of months, the next slightly improved iPhone will be released to much media fervor. You can jump in line with the rest of the Apple cattle and wait to maybe get one yourself.
Apple sucks you into a lifestyle, requiring you to buy more and more Apple products to use all the latest features. Their interface is proprietary, and that has always bothered me. It's marketing genius, but for those of us who would like our stereo to control our non-Apple mp3 player, we're screwed. I believe it should be universal between manufacturers so you're not locked into one.
Apple releases new models to boost sales numbers. Droids offer more options, and the market is more diluted by various producers, but they still hold a larger market share overall than Apple. Google is a strong entity to do battle against. They made a company worth billions off a page that had nothing on it. I believe that between the loss of Jobs and the Droid getting more and more polished, you're going to see more of a shift towards the Droid market.
I carry a Droid on Verizon. A first-gen HTC Incredible. I'll likely upgrade this year when it's time, not because the latest and greatest has been released, and I sure as hell won't be lining up at midnight to get it! I've played with iPhones and own an iTouch. I prefer the interface, customizability, and physical feel of the Droid by far.