In order to uninstall apps on touch-wiz, go to the apps folder then tap and hold the app and drag it to the uninstall box. Then tap yes when it says "are you sure you want to uninstall this application."

Also, while I realize this might vary from app to app, what would be some of the most common reasons/advantages to disabling an app?

The advantage of disabling an app over uninstalling it is that the app doesn't need to be installed all over again (from scratch using WiFi and the google play store.) Instead, you can find the app you want to use again and enable it. Think of it as a file in the recycling bin of a PC. It is not being used by the computer by any way, but can still be restored and put to use if you wish so.

In order to uninstall apps on touch-wiz, go to the apps folder then tap the left soft button. Now tap uninstall and touch the minus button for the app you want to remove. Finally, tap yes when it says "(App you chose) will be uninstalled". Here is a video showing how to do it: https://www.youtube.com/watch?v=TYL6nYapr7I

Also, while I realize this might vary from app to app, what would be some of the most common reasons/advantages to disabling an app?

The advantage of disabling an app over uninstalling it is that the app doesn't need to be installed all over again (from scratch using WiFi and the google play store.) Instead, you can find the app you want to use again and enable it. Think of it as a file in the recycling bin of a PC. It is not being used by the computer by any way, but can still be restored and put to use if you wish so.