Yo.
Android by a mile (or, if you prefer, ~1.6 km)
Things iOS does better:
Simplicity: It’s easy to use, and has a small learning curve. A lot less “tweaking” is required to get full functionality out of it, and most of the things you need access to, on the phone or in the apps, are right there. By contrast, Android often “hides” things via the menu button, and sometimes you can go two menu buttons deep! This isn’t intuituve for a lot of people (especialyl the two menu layers deep thing, though IIRC they finally stopped that,) so some people complain they can’t do XYZ, or it’s too hard to do it, because it’s more button presses, and might require more technical knowledge to set up.
Media syncing: For all it’s flaws, iTunes is still pretty good as long as you tell it what to do properly. Say you want this music on your iPhone/iPod, not this, update this podcast weekly, swap out this movie file with the enxt one on my list, etc… and it will do it automatically. By contrast, pretty much everything on an Android phone has to be either manually managed, or, at best, managed automatically within each app, so you might have to set three or four differentapps to each automatically do what you want…there’s still no good “single software” solution for ALL media files.
The hardware looks pretty: Even though there are a plethora of Android phones, eah with their own form-factor, I still think the iPhone 4 (hardware wise) looks best out of all smartphones. I didn’t care as much for the original and 3G/3GS…I prefer the less-rounded, metal-edged look of the 4/4S, and I’m upset that for all the copying of the 3G form-factor that went on in the android world, there han’t been any good copies of the 4S form-factor…probably all those lawsuits against Samsung for copying the 3G look. 
App selection: There are more in the App Store, and certain iOS apps that are really fun and/or useful, that have either no equivilent in the Android Market, a crappy knock-off, or (sometimes the worst,) a really bad, half-assed port of the iOS version that has crippling bugs, won’t work with all Android hardware, and uses too many resources because it wasn’t optimized for Android.
Things Android does better:
Pretty much everything else.
Custimization: Even though I like the look of the iPhone 4/4S, not everyone does…Android phones are so varied that you can get one that caters to you, most of the time (like isaid, no good knockoff of the 4S design, but jsut about everything else is covered.) Want a hardware keyboard? It’s getting harder to find them, but the Droid 2 is still selling, and Droid 3 is coming out soon…the Epic 4G, even though it has a “sequel” without a keyboard, is still being sold (and now cheaper.) There’s even one that has a portraitkeyboard if you’re coming from Blackberry (but don’t et it…the Droid Pro is terrible…but if all you care about is a portrait, hardawre keyboard, you’re covered with Android!)
And even amongst all the other ones that are touch-screen only, there’s options…small screens, large screens, cheapo-ones that aren’t as powerful, butget the job done, super-expensive ones that are “pure Android” and get all the updates first, and have the best hardware, etc…
You can also customize the software so much better on Android. Widgets are amazing…you can easily, right on your desktop/homescreen (Hell, even on your lockscreen) put one of any style of clock, battery meter, notifications for missed calls, texts, emails, etc…, a quick view calendar, and just about anything else. It’s really handy being able to easily check your upcoming appointments, the last few Facebook feed updates, etc… without ever having to navigate to or open an app.
Expandable storage: Not available on all Android phones…and with the newest version of android this might go away entirely (though legacy support will exist for a while, at least,) but most Android owners can simply swap out the microSD card for a bigger one for more space, or double their media storage capacity. I can also just plug my phone into my PC, click on ‘storage mode,’ and drag/drop files to it just as if it were a regular flash drive.
User-replaceable battery: Almost all (maybe even all) Android phones have use-replaceable batteries…real handy to have a spare or two to keep in the car, at the office, or in your bag/purse for when you run out of juice and either don’t have a USB cable, or don’t/can’t leave your phone “tied down.”
Standardized connectors: All current Android phones, to my knowledge, have to use MicroUSB to charge and move data. Many of them also have mini-HDMI out for paying movies on TV’s and such, too. Those calbes are dirt cheap on places like monocable, even good quality ones. Apple’s connectors can be had for cheap, but I have been burned by them in the past, since there is more “stuff” going on with them, it’s easier for a crappy knock-off company to made a cable that doesn’t work right. By contrast, microUSB has a whopping five pins.
More freedom in general: Google does not give two shits about what I do with my phone…now, the actual manufacturers and carriers care a little, but less than Apple does, and the trend lately is them giving the users more freedom…HTC and Motorola both raised a stink with their fans by locking down a coupel recent phones more tightly than usual, and when people complained, said “ok, we’ll stop doing that.”
So my vote is for Android.