Hearthpwn

I have an old security system in my grandparents' house. There is an alarm that does not as it is supposed to. I am going to renovate this house, no one lives there now. I have not decided yet, maybe I will rent it out. So, what about the security system. I have found a website of a company called Ajax. They produce a modern fully-equipped security system. There are different detectors, sensors, sirens. Could you recommend me this provider? Does anybody use this or any other brand? I do not want any DIY variants, it is easier for me to allow professionals the process of installation and support.