OP please read some reviews on https://www.rdforum.org/index.php, I've lurked this forum for a while and you'll find a lot of good independent tests from users.
The best advice you can get is that a radar detector is a tool and like all tools if you don't use it properly you can have results which are not what you expect.
Rule #1 - Don't be the rabbit! If you are leading the pack with no other car in sight out front, no radar detector in the world is going to save you.
Uniden R3 for $400 is the best detector out there at the moment, IMO! No arrows but I bet Uniden comes out with an arrow detector soon. Im thinking of buying one soon or just waiting it out for Uniden to come out with a new one with arrows.
Im still running my trusty Escort 9500ix. It has started to pick up more false K alerts over the past couple years with all the BSM shit but it still works great and hasnt let me down.