OptOpt let you bind keys with any application installed, later you can use those keys to switch/launch applications.
Hopefully this approach would need less key strokes when you are going to switch/launch an application.
The default action to bring the switcher is double tapping the "option" key in keyboard. Anyway you are allowed to change this default behavior in app settings.
Tips: I myself find its more convenient to use "caps cock" key as the trigger key, instead of "option" key, so I remapped it to "option" key in "System Preferences"->"Keyboard"->"Modifier Keys" to achieve that.
