In terms of apps, Apple’s app store probably has the upper hand. It has a staggering amount of apps, a very tight smooth and easy buying experience and is easy to use. The apps are also subject to content and quality restrictions wholy determined by Apple’s team who approves/rejects them. Whether this is a good thing depends on your position of “openess”. Apple’s apps tend to be of consistently higher quality and do not have the problems of viruses (as long as you buy from the app store and don’t jailbreak the phone and download apps off of 3rd party repositories like Cydia allows). Android’s market is fragmented relatively to Apple’s, which does give you tons of options in which app stores to buy from but the experience isn’t always smooth or consistent, and there’s not many people if anyone that are checking these apps for quality or safety. With apple’s stranglehold on the smartphone market, many companies and app developers tend to think of developing for iOS first then android, blackberry, etc. later. Though this will likely change as android becomes stronger.
When you get to the hardware, that’s where it gets complicated. Apple has complete control over their product, which allows them to sell a consistent user experience, on iPhones, they seem to be of pretty good quality, though probably wouldn’t want to test how much of a beating it can take. I’ve dropped it a few times and it’s worked great thus far. When you get to Android devices your experience will vary widely. Many manufacturers make android devices and some are better at it than others, and they are not consistent. Some will be totally touch screen, some will have keyboards, some with dual cameras, some with faster processors, some will have the basic four bottom buttons, some may have two or three, some will have version eclair of android, some will have froyo or gingerbread. From what I hear though, HTC and Samsung seem to make the strongest phones.