The UI part is easy if you are using Three20 (while some people might argue :p), the backend part seems very attractive as you don't need to have the knowledge

The UI part is easy if you are using Three20 (while some people might argue :p), the backend part seems very attractive as you don't need to have the knowledge to setup the web server/storage for serving the data, and need to worry about the scalability issue etc. Would be great if you also provide a CMS for editing the data.