I think this John Gruber quote on Siri explains why I use Android:
"...the whole thing still isn't up to Apple's usual level of fit and finish, not by a long shot. But I'm still glad it's there. I think the iPhone 4S is better off with Siri in its current state than it would be if Apple had waited until Siri was further along to release it."
If I had to distinguish between Google/Android and Apple/iOS, it's that each company decides differently whether or not a new feature is "ready" to put in.
Apple typically denies a new feature/product is necessary, secretly works on it for a very long time until it's polished, and then claims their solution is better than everything else out there. Sometimes this is very true (original iPhone), other times its marketing.
Google will see a need for a feature and put it in as soon as it is useful, even if it's not fully baked yet. They will then iterate on that feature again and again to make it right.
Google's approach means that people can take advantage of features sooner. It can be more difficult to discover these features because they can start so small and they get better and better in small and frequent chunks. On the downside, Google makes more missteps (Wave, Buzz, Google TV), and the ground shifts more rapidly (Android 3, 4).
Apple's approach means that new features are usually more polished and the additional fanfare helps users discover that they exist. But you have to wait a lot longer for them to arrive (notifications, Siri, cloud sync) and there are still mistakes (Apple TV, iTunes Ping, Spaces/Launchpad/Widgets/Expose mess).
It goes almost without saying that Google's approach is the web company style, and Apple's is the desktop software style: incremental, frequent updates versus major releases.
This is all just a spectrum, and Siri is one example of Apple straying a little more towards Google's side: releasing something when it is useful, but not fully polished.
So, I find Android has many more useful features *, and that's why I'm better off. YMMV.
* cloud syncing, turn-by-turn navigation, notification, desktop widgets, voice transcription, Face Unlock, Google Voice, customizable keyboards, Android Intents (apps plugging into other apps), NFC, etc...