Are you planning to develop mobile app for first time? Then which operating system, you would like to choose, Android OS or iOS. This actually may not be a million dollar question but it definitely is a catch-22 situation. If your mobile app developer is having the skills in any specific platform and you done have sufficient budget for hiring another app 
programmer, then you have to choose between any of the two OS. 

Android operating system, as per the latest reports own 83 per cent of the global smart-phone market today. Several thousands new users are getting added on a day to day basis. But from the monetization perspective its totally opposite. Apple OS is the front runner with a five times greater returns than Android OS. 

Apart from this, there are many factors, which should be considered before taking the final decision for the first mobile app. Following are those: 

Language
iPhone operating system (iOS) is written in Objective-C, while Android in Java. Java is more universal than Objective-C. Objective-C is cleaner than Java. Due to better stack traces, the process of debugging is a lot quicker. 

End User Experience
Regarding UI or UX, iOS has a clear edge over its rival Android OS. In high definition, iOS UIs looks way better and give a lot better experience. 

Publishing
After mobile app is development, either a hired mobile app developer has worked or it was done by a mobile app development company, publishing is a key. Publishing a mobile app on android OS is way easier than iPhone OS. 

Market Share
Market shares of the two platforms are very in different geographical areas. Check the popularity of each in the areas you are interested.

Fragmentation
iPhone OS mainly runs on three screen sizes: iPhone, iPad Mini, and iPad. Android, however, runs on an infinite range of screen sizes and variety of devices. Making you app congenial to all these devices will be a herculean task. Android app developers put a lot more effort on this to manage this is a right way. 

Before you choose between iOS and Android, you may take into consideration your target users and the special features of your app. For example, if you want to create a messaging app, android will be better since you can replace the built-in message app using the basic SMS/MMS medium. But in iOS, your developer will have to create a new communication channel. 

Author is a senior business analyst and an expert in native mobile app development.

Resources: 
http://www.mobileapptelligence.com
http://www.mobileapptelligence.com/ipad-app-development.html
http://www.mobileapptelligence.com/html5-developer.html