Seatposts

Lord Jimmy 7th
Lord Jimmy 7th Posts: 379
edited February 2016 in Road buying advice
Ok, I'm looking at these comfort seat posts like the specialized Cobl and focus concept cpx for example. But what I want to know is are hey really worth it? I currently have a 31.6mm post these are all 27.2 so guess I would require a shim? The bike I have is a ribble sportive if that helps.