Android users often harp about apps that are released first for iOS, but it's much easier to QA on a fairly limited number of devices, launch the app and start proving your idea/generating revenue on iOS first. At least in my experience, releasing a cross-platform app for both operating systems at the same time means either delaying iOS to QA Android properly, or releasing a half-baked Android version that gets 25 1-star reviews right out of the gate because of a weird edge case bug with some device you didn't test on.