Typically, iOS offers more user loyalty and revenue. However, this can make it difficult to get a good start; but once it becomes popular, it will grow exponentially. Also Apple is very popular in North America, Australia, and Europe. So, if that is where you target your app, there are lots of iOS devices in these parts of the world compared to others. iOS applications are typically easier to make than Android applications, however run a slightly bigger cost for publication. iOS apps can be run on iPhones, iPads and iPods, but cannot run on Android devices. If your app relies on early revenue or targets one of the countries listed above, iOS is a safe first choice. There are fewer apps to compete with and higher chances getting to revenue fast. This can prove to be a key choice especially if your product or startup requires capital to run.