Want advice on whether suspension seat post are worth it. Have a front susp. bike but have lower back probs so want to reduce vibration/impact on mostly hard surface riding. Any types reccomended? Cheers

They do work.. but like most things you get what you pay for. As far as I can tell the expensive ones all seem to work Ok, the cheap ones don't!
USE posts do seem to be particularly effective and reliable.

i use a USE XCR - very good. really takes the sting out of long rides. got a mate with a thudbuster and thats good too,though much more expensive.