Cupla days ago I replaced a USE suspension seat-post (that came with my Sirrus hybrid) with a Thompson setback seat-post, because my bike was a skosh small for me and I wanted to peddle with the cranks located a bit more forward relative to my body. Some observations with the setback post:
*An immediate increase in average speed; at least 1/2 mph better than my usual average on a 20 mile ride. I wonder how much pedaling energy was being absorbed by the old post, instead of transmitting to the wheels.
*No noticeable increase in road buzz. In fact no change at all. I do have a nice Terry seat on board, though.
*A significant improvement in tactile feel for the road. With the Thompson, I soon was corning much faster and acquiring a confident feel for the bikes handling that just wasn't there beforehand. It's like I did not know what I was missing when I was on a suspension post.
*A welcome end to that annoying left-right pivoting movement that suspension posts make as you pedal.
All in all, it was a lotta bang for the buck (actually it was $47 on EBay) and I would recommend it to anybody wanting to make their hybrid a better street machine.