The amount of cameras you can efficiently visualize through your Smartphone, will depend on many variables:
*speed of the router or switch that you have at home.
*the way the cameras connect: Ethernet or wifi, which will impact in the transmission speed.
*the way the camera's resolution is configured.
*broadband of the internet provider.
Our hub, Smartee, supports a transfer rate of up to 100 mb (10/100).
We are working on an Alpha version for managing cameras in our Smartee app, but in the meantime, you can install an Android app from Google Play such as tinycam (https://play.google.com/store/apps/details?id=com.alexvas.dvr) and in the free version you will be able to see 4 cameras at the same time, and setup up to 16 cameras.