The RVR315 offers excellent situational awareness. It sees cars you can't see in a mirror - the one approaching from out of the sun or the second, third, fourth, etc. cars in line behind you. It tells you how many cars, how far back, and how fast they are approaching. It announces their presence once they approach within 150 yards. This radar helps you be more aware. And being more aware, you can be both more safe and more courteous to drivers. I won't ride without this pod. Never ever a false all clear. Occasionally, it will give you a false alert - either a BIG cyclist coming up behind you or a road sign oscillating in the wind. But false alerts aren't a big deal.
I previously used the Varia 510 radartaillight but, when riding alone, I always wanted a much brighter taillight than the Varia offers. (I have a Dinotte Quad Red that I use when I'm alone.) When this radar pod became available, I bought it the first day. Now, I get the benefits of Garmin's radar and the brightness of my Dinotte taillight at the same time. Best of both worlds.