One thing to be wary of: abandoning the Mac App Store is going to make life much harder for you and your users in the near future. As of OS X 10.8, by default applications cannot be installed outside of the App Store (though a setting exists to change this):
http://techcrunch.com/2012/02/16/os-x-mountain-lion/ (scroll down to Gatekeeper)
Here's hoping that 10.9 doesn't disallow such installations at all (or void your warranty instead?).