Just try creating a mobile website that supports common "modern" devices. Have fun trying to wrap your brain around all the idiosyncrasies across various versions and browser implementations (Android Stock vs Chrome etc) that will endlessly dirty your code if you want the site to look at all correct in a majority of Android devices.
The Android emulator is pretty nice... once you figure out how to set it up for whatever device you're trying to test. It's a ridiculous resource hog though by default (there are ways to mitigate this if you're on an Intel chip). Say what you will about simulation vs. emulation but the iOS Simulator is a dream to work with (again, for web development) and I've never had it mislead me even though it isn't truly emulated. But then you realize there is no way to install the Chrome browser unless you are hooked up to the Android Marketplace (even if you're on the latest version of OS). The best you can get is Chromium, which is a pain to install and doesn't work on some AVDs.
All that ranting aside, I've never had a problem with screen sizes, even when working on responsive stuff. But, yeah, Android is basically the Internet Explorer of the mobile space. You'll keep hearing "oh the next version will fix that!" and it may... but you'll be stuck supporting the versions that are broken for years to come.