Went for my first ride with the SR Mini Radar (or any radar) the other day. While not a "game changer," I was surprised at how much of a benefit it was. I didn't have any false positives or false negatives. I noticed that the radar alerted me to a vehicle approaching about twice as far as I would have noticed with my "spidy-senses."
I am a big proponent of taking the lane when needed and that bikes have a right to use the road as much as any other vehicle. But I also believe that riding as safely as possible is more important than "the rules" or my rights and that being a little courteous at times is the best action. So previously when riding (without a radar), by the time I "sensed" (or heard, felt, or however realized) that a car was approaching from behind, my normal reaction was to hold my line, because it wasn't usually enough time to move without making it a really sudden move. But I found that with the radar, I could gently move over, well before I would normally. And I think the perception by drivers is positive – noticing that almost all the drivers moved over as well. I do fully expect the same occasional jerk passing closely on purpose, but just on this one ride more drivers were giving me more room. And mind you I'm not moving over very much, on one stretch of road where there's a rumble strip about 8-10" to the right of the while line and only about 10" of shoulder remaining on the right of that, and I would basically ride on the line on the left, and when alerted by the radar move the few inches to just on the right of the line or between the line and the rumble strip.
Anyway great product and about half the cost of the Garmin version.