The important thing to remember is that there are a number of functions that your security control can perform. All controls should be equipped with a rechargeable standby battery to power the system in the event of a power outage. You should have sufficient battery standby to operate the system for the duration of outages you are likely to experience in your area. Most controls can be equipped with enough batteries to power the system for up to 80 hours if needed, although some may require additional charging modules. The amount of batteries needed depends upon the type and amount of devices used and how long you want the system to function without normal electrical power.
Security systems can use wired, wireless, or a combination of wired and wireless devices.
The type you use depends upon many factors such as ease of wiring, building construction, timing of the installation, and cost. Wireless systems have a much higher equipment cost and require battery changing every few years, but can be installed very quickly. If your major concern is disruption of your home routine, then wireless may be a good option. Wireless is also good when you want to have detectors installed in unattached garages or sheds. Some controls are either one or the other but many manufacturers have introduced controls that allow both to be used as needed.