PhoneWatch were bought out by a Norwegian company, Sector Alarm, so now they only install their own outdated and overpriced equipment. They also only install a very limited number of sensors, the systems they recommend will only detect a burglar once they're already in the house. They try to convince the customer this is all you need, asking for further protection/ sensors quickly escalates the price to the ridiculous. So a burglar could enter through a bedroom window and have free run of that room, and perhaps others before passing by the one or two internal motion detectors triggering the alarm.
Most other alarm providers will recommend a proper perimeter protection system that will trigger as someone attempts to break in, so more likely to put them off entering in the first place. With all other alarm providers, you will not be locked into the most expensive monitoring in the country, and will have the option of shopping around every time your contract comes up for renewal.