There really isn’t a short answer to this question but what I can say is that much of the difficulty depends on the support you get from the company you have chosen to provide your product. I have owned a local security company for 20 years and I am often selling my local DIY security products and services against the national chains like Simply Safe or ADT. The best way I can put this is, what company do you think values you as a client the most and will take the time needed to help you make sure your system is installed correctly? The difficulty of the installation process depends on your own ability and experience with self-installations coupled with the support your receive from the DIY Security Vendor.
My greatest fear as a small security business owner is that a detail is missed by one of our DIY customers during their self-installation and the system does not perform as expected or designed. In the past, for my own custom installation team, I would hammer in the concept that it must be done right, “failure is not an option” to quote Gene Kranz mission control for Apollo 13. Now our clients are doing it themselves? A little unnerving for a long time security guy like me. I have lost some control over how the installation is really being performed. What I can control is the amount of effort, time and energy I put in to making sure our DIY clients have the resources and the customer service to help with the process of installation. In my mind, a DIY client is no different than a client that my technicians have installed a system for, they might just be a lot further away.
So pick your Security DIY dealer carefully knowing that you may very well need their expertise and support during the installation process. In my experience larger national companies just don’t place the same level of value with each new DIY security customer. Every account is so important for success with small companies they don’t have the option to let service slide. And if they do, they won’t be around for long.