EagleEyes(Lite+) lets you monitor your business remotely, but it's really limited in its reach. EagleEyes won't let you view cameras from any old manufacturer, but it's a decent app to have if you use a specific type of surveillance software.
EagleEyes only works with AVTech surveillance equipment, so look for another app if you don't use that. If you do use AVTech, this app gives you enough features and seamless operation in the free version. If you want full control, you'll need to pay $5 for the pro version. Either way, setup is easy. You can connect your Google account for a quick install, if you want. If you don't, this app can still track down your cameras with only a few bits of information. It supports typical smartphone gestures to pan and zoom and will even vibrate if something is happening on your cameras. The app's jet-black layout blends in well with CCTVs.
If you already use AVTech equipment, this app will be a welcome addition to your smartphone. You might be more interested in a universal app if you want to monitor different kinds of cameras, though. If you don't, give EagleEyes a shot before you stray to third-party cam viewers.