I have the 715 and it has probably saved me from a few points over the last couple of weeks. Not the most expensive out there but it does detect live Gatos (if radar operated!!). Travelled out of London at very late hours the last two weekends (like between midnight and 3am..). Sort of time where you can travel quite safely at 70 on 50 signed roads (like the A3 south to the M25) because there is almost zero other traffic.
As I don't travel these roads so often now I forget where all the cameras are. BUT I do know they are there and I know what the limit is. A couple of times the 715 has bleeped and I've slowed and then seen the camera. Good investment in myopinion. and a LOT less than other detectors on the market.
The others are right. It does get a lot of false alarms BUT mainly in town and so they only really bother passengers.
Not had a laser pointed at me yet but those ar so quick I wouldn't be surprised if I got caught out.
Dave