This is my first install of an alarm system. The cabling was run by electricians during a rewire. It needed twice as much cable as that supplied for a 3 bedroom house including a 20m run to a detached garage. In addition to the equipment that was supplied in this kit, i also bought 3 * menvier 12v smoke alarms and 2 dual-tech PIR's for the garage and one other space. I only use one of the door contacts, and use PIRs instead of the other 2. Although the main box only has 8 zones, you can wire more than one device into each zone - within contraints. Zones 7 and 8 can be configured as fire zones, which means they're effectively always armed. The panic button does not count as 1 of the 8 zones. In total i have 5 PIR's, 1 door contact and 3 smoke/fire detectors (2 are in the same zone) running off this system.
The PIR's, even when set to 25kg have still been tripped by my small labrador. In the 3 months since installation I have had one false alarm from a PIR, which i'm currently putting down to the heating coming on at 6 and the sudden change in heat triggering the PIR.
This is not for the faint hearted novice. I would estimate that it took me maybe 48 hours of work to get this thing up and running. But it was fun, if that's what pulls your chain, and your neighbours will hate you for a while.
One complaint is that the two screws that hold the panel onto the the main control box should not be able to just fall out. I've lost three so far, and they're hard to replace. Bad design.