Ive installed several systems for clients and have my own, from my experience the swann kits with cameras and recording unit are the simplest and most robust, but get as high a resolution as possible. I had a client who has a trailer stolen, they saw the car and the thieves on the camera, but it was only 4m from the camera and the license plate couldnt be made out as it was only a standard composite cable camera.
The police didnt do much, they knew who the thieves were, they knew who had bought the stolen trailer from the thieves, and yet the thieves havent been prosecuted and the trailer hasnt been restrieved.
Makes me think americans have the right idea for property defence.