We took a different approach in terms of business model for several reasons.
First, we wanted to be aligned with the iOS app.
Also, we believe we are providing a Premium experience. So we are asking for a Premium up-front payement. It is also easier to maintain. We prefer to take time to build future features ;)
Finally, we are building some features that will be difficult to support in a freemium model like notifications, email reports and other server side awesomeness. Offering a part of the experience for free and then unlock everything with an IAP is not in our DNA.
Hope it makes sense…