Garmin Varia RVR315 is now almost half off, down to $82

I have the 515 with the light. Half of why I like it is that it flashes when folks get close, so a little more visibility and it alerts the folks drafting if they aren’t otherwise aware. As far as the radar itself it’s most useful on relatively unused roads when you might not hear the car coming and aren’t expecting it. On busy roads it can become one more ignored signal. It also tells you just that someone is coming up on you, but not whether they are likely to hit you or not. I’d say it’s a mix of useful info and noise, and most useful with the light included.