I've got a cheap one. I like it. I wouldn't say it's saved my ass on several occasions. But I'd say that about 20% of the time that it beeps, I see a cop pass by a moment later. That's in the city of course, when it detects the little onboard full time radar guns that cop cars have up on their dash. I've yet to encounter a speed trap with my detector, though, so I can't say much about it's performance in that area. Passengers think it's cool though, makes me look like a badass. I'm going to install like 3.