For mobile apps, if you're a single developer, I think going with a single platform is fine. You can only do so much, and if you're familiar with the platform, you can move much more quickly than having to support two. That's the strategy I've chosen and it's helped a lot because I was already an expert in iOS and a lot of the work is just "figuring out what users want" and it's easier to change your code on a single platform that you know really well.