Autowatch and Cobra make most of the 'traditional' alarms (Mongoose M60/M80 and umm, fill in the blanks...) look pretty arse.
But it all comes down to the installer. My old alarm (which the previous owner had installed) was a '5 star' but the brain was tucked up on top of the steering column, loom was looped around in the same area, and the bloody drivers door switch wasn't connected. It had glass break sensors which are a complete waste of time on a Subaru. A $200 chinese single immobiliser alarm, installed extremely well, will protect your car better than a badly installed '5 star'.
In Wellington, I would say that vehiclesecurity guy definitely knows his stuff, and I get all my alarms done at SLAP, who do a damn good job IMO (watched both my alarms being installed and I know they go the extra yard)