- iOS will be around a long time.
- Big brands and startups are basically required to have an app in the App Store if they want to succeed.
- Every year a new version comes out that requires developers to fix bugs and sometimes adopt new technology.
Here are the cons:
- Extremely difficult to build an indie business on iOS given that there is a single distribution channel that you don't control.
- The learning curve is pretty steep.
Here are some other points:
- Good iOS developers are harder to find than good web developers (feels true to me, it might not be).
- You probably won't be on call as an iOS developer (this is important to me, it might not to you).
Developers are paid well across the board. I would pick a technology you enjoy working in and isn't in decline. I believe developers are more likely to succeed if they chase their interest over their salary.