In my humble opinion...
I was a Police Officer for a couple of years and since then I'll never spend a single dollar on a radar detector and here is why...
1) Cops know that detectors are on the road so how do they beat them?
By leaving them off and toggle them on and off when the vehicle visible to the officer. Therefore if you are riding along on a turn or hills and you have no warnings on your detector suddenly your detector goes off and then stops, then its too late. Your speed is locked. It's not hard to for the officer to know hear and see when a car is coming and as soon as he knows you are at a distance to get a positive lock on thats when he flips it. Its even easier for a cop to know when a motorcycle or rice rocket car is coming (sound). It's the lazy officer that just leaves the radar on hoping for a speeder without radar.
2) I like most cops only leave the radar on during calls. Why?
Because cops know that detectors are on the road so if the officer is going to a call or to lunch or the donut shop (insert jokes here) and going from point A to point B with no intention of stopping then the majority will just drive with their radar constantly on just to slow everybody that spent hundreds of dollars on a detector that is making them slow down for a cop that is not even tracking them or has any intention of pulling them over. It's a plus to cops that they are making the roads "safer" with just leaving it on. Everyone with a radar detector thinks their radar is saving them from a ticket and that it was totally worth it but its a sort of reverse psychology just to make you slow down.
3) What's the tool of choice the majority of cops that perform traffic enforcement use?
With the current technologies lasers are the preferred method of tracking vehicle speeds by departments that actually have a traffic division (cops that do nothing but traffic, accidents, speeding tickets etc).
Another point and shoot when you are ready tool for traffic enforcement. Not constantly left on so radar/laser detectors just alert you after the fact that you have been zapped. The way to beat that is laser jammers which returns a scrambled or error message back to the officer. Jammers are best utilized with a sort of warning device (lights/sounds) so that you the rider knows that a officer is attempting to lock on to you repeatedly so that would be your cue to slow the hell down now. Reason why is that savvy cops know that their lasers are not meant to give error messages and if they know that you're speeding with their calibrated eye (insert more jokes here), and not slowing down, especially if you're driving something sporty and expensive, then the chances are that you can afford a laser jammer and they will then pull you over under a bogus PC (probable cause) just to inspect your vehicle to see if you have a easy to find jammer tucked behind a fairing for bikes or bumper/grill for cars.
As for me, I'll never waste money on a radar detector but to each their own. I think you're better off using your head and especially your eyes to scan for cops in their usual hiding spots (after blind turns, hills, tucked in commercial parking lots etc) If I had the money to spend (about 1k or so) , I'd invest in a laser jammer but until I have everything I want on this 1199 (CF, pipes, bling) I'll hold off.
Ride safe and don't day dream while speeding. Keep an eye out and scan for cops