The app has already replaced both AppSniper and the App store for me in terms of browsing, searching, and keeping up with sales/new apps. But I do have suggestions.
1. Change the name. Store-Extend is.... lame. Sorry I can't think of a better one right now but it definitely needs work.
2. Email my brother at
cyrilshark@gmail.com and he will probably be willing to make you a free icon. Make sure you give him any design specifications though such as icon size, ppi, all that stuff. He's not exactly a professional yet, though I'm personally amazed at the stuff he can do.
3. Model your app after the appstore interface-wise, but with the additions you've made. This makes it familiar, but improved.
4. I'm not sure what content you have available, but adding Apple's featured, *new*, and staff pick lists would be awesome. Also I'm not sure if you can but linking the app to people's iTunes account to list their updates would be a great feature, bringing you that much closer to replacing the app store entirely.
5. In appsniper, when you open it up it highlights all the apps that received price drops or are new since the last time you opened up. That'd be REALLY handy in store-extend.
6. Consider adding another list for updated apps. But if you do this, be sure to include the update-log if possible!
7. When I click to go app store for an app in my favorites list, do what appsniper does and offer to remove that app from my favorites list.
8. I've noticed one bug, sometimes descriptions get messed up. There was one that had a completely unrelated description, and another that had the description from a previous update. (I checked it against the app store).
Good luck and thanks! Nate