I've just installed a Visonic PowerMax + system for a friend of mine. The initial setting up of the sensors etc is much much easier than other systems I've installed. The fact that it is totally wireless, well except for the power connections and telephone, makes locating the alarm panel and Siren box a much easier task.
I would also recommend the computer interface as this makes programming the options quicker, since it can all be done from the pc then downloaded to the powermax +. This saved a lot of time.
If any one is thinking of buying an alarm or getting one installed then I would recommend a Powermax +.
If you want to use wired sensors then there are 2 zones designated for wired sensors. Also Visonic do a special transmitter that can turn any wired sensor into a wireless one.
For an in depth review of the Powermax Alarm panel try here