It definitely shines in a more rural/non urban setting for sure. That’s mostly where I ride.

That said, it’s also highly useful in urban areas be cause you can see how many cars are back there (most of the time) so you have an idea of when you can take the lane or release the lane. I would note that it doesn’t replace a look a back and it is synergistic with a mirror. I use the tiny Specchio mirror on my glasses and scan it just as if I were driving a car. The Varia Radar is great to interrupt my scan since I know that there is a car approaching. Since I ride in a predominantly rural area on high speed roads, that’s the time to look back because the speed of approach. The Varia gives me about 5-6 seconds of warning and that’s enough to see if I’m going to be ok or have to evade.

I’ve been riding with the Hammerhead Karoo as of late and it’s implementation of the Varia Radar is superb and class leading, IMO. I also have the Wahoo ELEMNT and an Edge 1000. All of them work well.