I set up one of these for a guy about 4 years ago that had 8 cameras. We setup a standalone PC as a DVR. The power supply was standalone with a UPS to record for an hour or so after power was cut off. The PC went into a secure box with it's own UPS and it uploaded video to a remote server. So even if they cut power and destroyed the camera PC, we had evidence.
The cameras were pretty normal color day time/ infrared night time with the LED things and the domes. They worked ok, but you couldn't see the whole backyard at night. The best solution IMO is an infrared flood light that can shine all the time. A regular flood light with motion detector makes a flash and it takes the camera a while to adjust, and if you don't have a light on the camera can't see the motion to record. So if you just keep an infrared floodlight turned on it seems like the best. I dunno it depends on the situation and a lot of things.
But as far as I have seen, the cameras haven't improved dramatically. And that's really the biggest problem. The DVR's are nice, but you need decent quality video at all hours of the day.