Besides the user interface adjustments that make each mobile OS unique, one of the biggest differences between Android and iOS is access to Google applications and services. Yes, both operating systems have web browsers that can access Google services, but native application support is a pretty big deal in both worlds.
On Android there are Google apps a-plenty. Google Calendar, GMail, Google Contacts, Google Maps, Google Talk and YouTube all built into the OS. Google Voice, Tasks, Reader, Google+, Google Docs, Google Currents, Google Chrome, Google Books, Google Movies and Google Music are all available via official apps in Google’s Play Store.
On iOS, the situation is very different. Google Maps comes built into the operating system, and there are a few apps available from Google in the “App Store,” including Google Earth, Translate and GMail. It’s possible to get Google Calendar to sync with iCal, and GMail is hit or miss with iOS’s mail client. To cover everything else, Google has an application in the iOS app store called “Google Search,” which provides a shortcut to several webapps like Reader, Voice and others. This isn’t much different from visiting the services in the mobile web browser, but it’s a step in the right direction.
The point is that the more heavily you rely on Google services, the more you want to consider how well they are built into the OS. Google has done an amazing job with ICS and its built in services. All things considered, what’s your setup like? Are you a heavy user of Google apps and services?