Sparrow Founder Tells How He Made $350K, And Praises Apple's Walled Garden

Having just launched a Mac app, I can definitely say that the Mac App Store market is really wide open for developers right now.

The main caveat is that Mac development is a lot more challenging than iOS development, especially if you want to create a custom shiny user interface like Sparrow's.

Simply put, the AppKit APIs are not nearly as nice to work with as their iOS counterparts.