Best camera security system?

[Joe Meares]

Hi guys,

I'm working on a 6 unit apartment building, and would like to purchase a camera based security system. This is my first time working on a multi-family and I know next to nothing about security systems. Is there a gold standard company or set-up for apartment units of this size when it comes to security cameras? Looking for something reliable and affordable. Even if you can point me in the right direction of the place to learn more about this topic, that would be great too. 

Thank you!

Joe