Matt Gemmell weighs the pros and cons for each releasing in, and outside of, the Mac App Store:
I recently released a new little Mac app, Sticky Notifications. It’s not currently in the App Store, and accordingly I went through a process that many Mac developers face: deciding whether to release software on the App Store, or outside of it (or indeed both). […]
Firstly, let’s weigh up the App Store against releasing software on your own. This concerns the Mac, primarily, since you don’t have a legitimate non-App Store option for iOS devices. The pros and cons of the App Store (listed below) do apply to both platforms, of course. We’ll discuss the App Store route first.
Gemmell makes a list of “Scary Things” when selling one’s own software outside of the App Store. There are an awful lot of things to recreate, but luckily, the Mac App Store is relatively new. The problems faced with selling software on the developer’s own terms are decades old. These problems all have solutions.