The cameras and the DVR are, to be blunt, complete garbage. Frankly the value simply isn't there because you're trading too much quality for the price reduction. (There's a reason the cheapest DVRs I or any other installer would ever use for an installation go for around $300; the drawbacks of the cheap units don't outway the price diference) Although, if you are looking for a method of deterrence, these will, barely, get the job done; the cameras look puny and the brackets will sag / move over time.
My biggest complaint with these cameras is their horrible resolution and picture quality. 320 vertical resolution, interlaced mode, cheap sensor and cheap processing all lead to crappy image quality. This becomes a problem when you need to take a still-shot from your video to identify someone, and since the picture quality is so grainy and crappy, you will NOT be able to identify the person 9 out of 10 times.
I guess it's better to buy and install these cheapest of the cheap cameras than to have none at all. Other piece of advice, if you buy this kit, install large signs (usually ~10"x10" in size) as an additional deterrent (Funny thing is, the signs cost more than these cameras).
PS do not run your cable like the guy in the video....