Everybody is going to have an opinion so take it as that...
In the last 15 years I've owned, in order, Escort's original Passport(Dad's hand me down), an Escort 6800, a Bel 945iL and currently a Valentine 1.
Since the first detector I've always wanted the Valentine but it was too expensive. Well, now I can say it's wholly worth it. While the others worked well enough, the V1 just blows them out of the water because
(1) it visually tells you where the source is ie forward, backward or to the sides. It goes off and you know exactly where to look.
(2) it tells you how many signals you're getting. Ever seen a cop running a trap and then another one 1/4 mile down the road picking off the people that assume it's safe to speed again? Or what happens when you ignore the warning because the detector always goes off in the same spot from an automatic door at a store. Well one day there's going to be a cop across the street using it as cover. The V1 tells you theres a second signal.
(3) Sensitivity and antifalsing. Unbelievable. I even got to test it one day with a guy riding alongside me. He had some kind of cheap detector. I got a serious warning of an upcoming trap several seconds ahead of him.
The damn thing has been on top of the Car & Driver test just about every year since 1990. And they do very rigorous, real world testing. The Escort and Bel always topped the Whistler/Cobra/Uniden POS.
Laser basically nails you...the beam is so narrow, the chance of picking up scatter from a previous trigger is slim.
There are several laser jammers that run the LEDs up front that difuse the beam. The cop will eventually get you but he has to retry several times, giving you some warning. Lidatek, Escort and Bel currently make them...running from $300-500.
There is also another countermeasure device. It's a function of some of the models of Bearcat Scanners. It detects the trunk mounted proximity beacon in 99% of all emergency vehicles and alerts you when you're within 3 miles. Unfortunately, this is also in firetrucks, ambulances and various government vehicles. While this would be useless in town because it would always be on, its a godsend on long freeway trips. I used one on a trip through west Texas and New Mexico. It's basically an early warning, first line of defense. It also helps that it scans the CB chatter...truckers are great at sharing radar trap information.
Both of those second items are on my wishlist. But first, you need to buy the best detector you can afford. Skip the Whistler, Uniden, Cobra and anything else that claims to passive jam radar.
360 detection? Radar only works front or back so anything to the sides is harmless.
Another great item is for blocking photo radar. It's a plate that goes over your license plate. It's clear except from typical photo angles when it obscures all or part of your license plate. The photo radar detects you speeding and snaps a picture but there's no plate number to trace it back to you because there's a mysterious glare.