Clever idea in that it can simply replace the saddle in the seat post and it is adjustable for pre-load. My only concern is concentrating so much force is such a small bending area. The springs on a Brooks Flier, for example, spreads the bend out over, probably 12 inches, if we were to take a spring off the saddle and unwind it. I will guess that this bending area is about 3-4".

I'm interested in hearing reviews.