I bought this last summer and FINALLY got it installed over the Christmas holidays. Have not been on a ride with it yet but I like it. I'm only using the chase light and brake light functions. It doesn't seem overly bright. I've been wanting something like this since I'm usually the one leading the group and navigating.
My father-in-law has a single LED flashing light on his buggy on the front and back so we can locate him in the woods. It works great. Sometimes he will stay at the back of the group so I can always see his front flashing light.