The problem with ghost hunting apps are that they really aren't that reliable while conducting investigations. Why? Lack of functionality, no multitasking and energy drain. The reason why many big name paranormal investigators have a wide array of gadgets is because you need to capabilities that a iDevice or an android phone would never be able to handle like taking infred photography, true heat detection, and the ability to detect electromagnetic variances. Also, if the capabilities that those devices can handle, a problem lies with the fact that you could only have so many programs running at once so you would be stuck with looking at heat detection or em readings and not both at one time.
But even if you have the ability to do everything with a magical iDevice or a magical Android at once, would you really want to only have one device with you when you know that many spirits like sapping electronic devices for energy? I've had several newly charged 4 hour camera batteries die on me while in a cemetery in the past, so I wouldn't want to risk placing all my bets one battery I can't remove from the device.
