If you're selling iOS apps, you have no choice but the app store. You could try giving the app away for free on the iOS App Store and shunting people to a website to purchase the license after a certain amount of time, but I'm certain that breaks Apple's rules. Same goes for the Mac App Store.
You'd get shut down pretty quickly if you ever managed to squeak through the approval process.
Based on the code examples provided on the website, I don't see any of the most popular languages use for apps that go in an "app store" of any kind (Obj-C, Swift, Java)
I'm sure intent is not to be misleading, but I don't see how this can recoup a 30% app store take. Could you explain that in more detail, since you are replying in this thread?