[augustus]

I developed a webapp (project management) before deciding to go native.

Some of the additional reasons why I believe users prefer native apps are:

1. The app store app and iTunes make it easy to discover native apps. Webapps are simply posted on a link from apple. This makes it harder for users to discover them. Here is the link to webapps: http://www.apple.com/webapps/

2. With native apps, users can take advantage of built in UI elements reducing the learning curve and creating richer applications.

3. Web apps can suffer from performance issues especially when you are on an edge network.

4. Payment processing was already mentioned. Its an issue but probably not a huge one.

I think the native look and feel and Apple's own promotion are the two big factors in favor of native apps.