Both Single App and Guided Access can appear as a kiosk.
Easy to setup. Simply click in settings and triple click Home Button to start.
|Restarting phone will cancel guided access.|
|Can easily change or adjust the app.||Password can be guessed.|
|Doesn't need external computer to setup.|
Applications exist to make it easier to go through all of the steps. Like a free app from Apple called, Apple Configurator.
|Needs a computer, specifically Apple, to setup with Apple Configurator, which is free.|
|Better Security, restarts go back in directly to the App.||To cancel needs an external computer, and depending on setup might need the exact same computer.|
Just a quick back and forth between the two.
If your just demoing something for the day or showing multiple applications, a guided access is useful and probably the right bet. Best for when the person showing the application is on hand.
Otherwise, if this is going to be locked up and left on its own use the Single App mode.