And they're a lot more different as well.
On iOS, you design for a couple resolutions and maybe one iOS rev back, you test on a 3 or 3S for performance, you put it in the app store, you wait a few weeks for approval, and then people pay for your app. Apple takes a large cut (30%) for the privilege.
On Android, you design for the least common denominator Android rev (2.2), you add gobs of code to make sure the application scales properly depending on the resolution, you discover that a large majority of the devices out there have even worse performance than the iPhone 3, you put it in the app store, you get immediate approval, and then people start downloading your app, sharing it around, and installing it for free without even jailbreaking their phones. Meanwhile, you're constantly fixing bugs on the various editions of the platform, to the extent where it's very unlikely that you can actually make money because Google also takes a large cut (30%) for the privilege.
As a user, you can buy and download a new app on the Apple store and be reasonably sure it's fit for purpose and works as described, but only Apple decides what you can buy (not a big deal in practice). However, with the Android store there's a non-trivial chance of getting malware or paying for some crap app that doesn't even boot (see the class action suits, etc).
YMMV, and opinions are strong on both sides. For consideration, though:
http://www.gamasutra...ill_Favor_iOS.php
Another significant factor is revenue: Flurry's figures show that multiplatform developers are making an average of only $0.24 from Android releases for every $1 spent on their iOS counterparts.
The firm looked at in-app purchase data for apps with several million daily active users before coming to that conclusion, and cited issues like OS fragmentation, low Google Wallet penetration, and lack of Android Market curation to explain the gap.
