@Anthony Kennedy Go with BI. I bought a camera system with NVR system 3 years ago and never once opened or used it for anything. It is terrible. I didn't like the software it came with the NVR to watch on computer so I looked for alternatives and found BI right away. After looking into a lot of other options BI had most options for best price. Then I found IPCT to set up BI to make it better. I am going to setup a BI machine to run all cameras vs a NVR.
You are lucky that you are finding this information before doing the wrong thing and spending more time and money. I am newb and once you learn how to set up bi is very easy. This person has a nice setup you can follow a bit:
My humble setup so far....
I am not sure how the installers works but they should be able to run wires and install the cameras you purchase. Look at the dahua suggested here with the reviews.
I have always listened to the advice of IPCT and Fenderman a lot and it never steered me wrong and I was never unhappy with their suggestions even when I thought I "knew" best. Go with BI system and you will be very happy with how easy it is once you set it up and the flexibility. NVR will not come close to it.