Extremely easy. You can quite literally start from not knowing anything about Android development and, in an evening, have a simple app up in the Marketplace.
...and before anyone responds with "well, that's just going to lead to a bunch of bad apps in the store," I ask you to count the number of fart apps in Apple's App Store. Though I'm sure they're all quality fart apps...
I'm a developer for a very large Android app that touches more system components than most and we have no place in code where we check for OS version and exactly 3 places where we check for a very specific (bad) phone.
"pop your app up on the App Store" -- after going through Apple's gate. In the Marketplace, we deploy on our schedule, not Apple's.
...and before anyone responds with "well, that's just going to lead to a bunch of bad apps in the store," I ask you to count the number of fart apps in Apple's App Store. Though I'm sure they're all quality fart apps...