Within a couple weeks of buying my older 1992 conversion van (in 2011) I had an alarm installed. It was an
Avital. I dont know if you have Angie's list but that is where I found the installer. I live in the city of Milwaukee. My van is parked on the street year round (except when I am traveling). Cars are broken into in the surrounding blocks despite our living in the lowest crime are of the city. I do try to keep my van pretty close to the house so I can hear if the alarm goes off. While I have had the alarm go off when I accidentally hit the panic button for a couple seconds, there hasnt been any false alarms and nobody has broken in either ... so far. Now, we left a little, truly ugly pathetic trailer brimming over with construction materials on the street with one of those "tongue locks" overnight and it was gone in the morning. We have had 3 trailers stolen until we finally put our trailer into a garage.
We do have thieves working the back alley and breaking into garages here. I would highly recommend motion alarms along the fence especially where the gate is, and we recently installed a door to our side yard that has a bump-proof, double keypad lock (Lockey M210DC Keyless Double Sided Deadbolt) which prevents them from getting in and then opening up the door and dragging or carrying stuff out (not that there is much to take).