I use a radar detector in my cars and love my Valentine One. The arrows make all the difference. Other than that, most of the top detectors all will find radar in the vicinity, but only the V1 tells you approximately where it is. You learn to read the arrows and get very accurate. Helps to know if they are coming from behind, or in front or the side, and if you just passed them or they are still coming.

And No, I don't use it to speed. I stick to between 5 and 8 over the limit, one mantra being: "8 you're great, Nine you're mine" (from the cops perspective). A GPS helps because you can see how far off your speedo is.

As for the bikes, I don't have radar on them, I don't speed that much, and especially on the bike, the main group I ride with (STAR) has a rule, obey the law.

But I used to get all sorts of grief from various people on rides (as I was ride captain) about being too fast or too slow. Well, I had checked my speedo with those roadside radar things and by having several cars pace me, but the GPS I now have shows my speedo is exactly 1 mph fast at highway speeds. So I can tell all those that gripe, I am spot on, and they need to check their own speedometers!