i have an old $70 Cobra. very small one. it saved me everytime. never got a ticket in my whole life (knock on wood). but i think the only way to use a radar detector is only if you know how to use it. several of my friends who has radar detectors was like "wtf, i don't see no cops" but it was just a local store.
the best way for me to avoid being caught is, know your police cop cars. there are SEVERAL unmarked police cars here in Oklahoma. the only way to detect them is by their hubcaps. i can tell between a gangsta impala to an actual cop car. secondly, this is my strategie on the highway. when you see a car passes by you REALLY quick, i would follow them about 6 cars length away. supposely, that car will either brake when he sees a cop OR if his radar went off. by then, i will have more than enough time to slow down so the cop won't trigger the gun at me. this has worked for me several times.
for the times i'm almost caught, i would run into a neighborhood and wait about a whole 10 minutes. LOL! but yea it's true, i never got a ticket before. wish me luck so i can have a no-ticket record when i'm 21! (i just turned 20).