I have experience with both of the following radars, and highly recomend them. However they are not for people on a budget:
Valentine 1:
$300 new. 360 degree detect. 3 mile radius. Arrows pointing to cop direction. Track multiple cops at once w/o display changing.
Rocky Mountain Radar RMR-C450:
$350 new. 360 degree detect. 180 degree scramble*. 3 mile radius. Track multiple cops but changes display. 100% active laser scrambler, passive K, KA, X band scrambler. A tad bit slower then the V1, however scrambling feature is nice, and it has better POP radar detection.
*The scrambling feature makes this radar illegal in about 15 states. It is not in IL (As i own one, and have checked local laws). Only the laser scrambler is active, the rest are passive. They do not stop the cop from seeing your speed, rather cut the distance in which he can get an accurate reading.
Both are great and it just depends on what you need.