I've had a Utopia backrest for about a year. I like it in many ways, but the gap between the seat rest and the support rail is open and unpadded. Last weekend I took a ride and actually came home with bruises on my lower back.
Yesterday I put a rolled towel in the space and it was a tremendous help. This is not a permanent solution, However, because it tends to fall out.
Anyone else have this problem and what have your done to solve it? Great opportunity for the manufacturer, I'm certain of that.