In my experience, people who claim to do both iOS and Android development well vastly overestimate their abilities. At the highest levels, writing an iOS or Android app is like being a game developer and pushing the platform to its limits (in a non-hacky way). To attack the problem of smooth scrolling, ~60fps on a list (especially one doing async fetches and/or database and/or complex cell layouts) requires different experience and knowledge on each platform. To build a beautiful app (not an average app) on either platform, requires almost a craftsman-level touch and level of care. To attack the problem of data synchronization... don't go there (just use Parse)