Matt
The Thorn Comfort Bars are great if you are ever thinking of changing from the Humperts!
The Suntour SP12-NCX suspension seat post was something I looked at as I thought the Thudbuster was a bit expensive. So I googled/looked around. I was not looking for total suspension post but something that would absorb the big bumps while effectively acting as a solid seat post. The Suntour seemed like a good option. Reviews were good too with some saying they preferred it as it did not bounce up and down all the time. The Suntour can be adjusted so it 'bounces' when you want. I fiddled with the spring setting after I got it and have found the perfect setting.
I have not tried the much acclaimed Thudbuster (which does look good and it would be useful to try in comparison) so no first hand experience on that.
I find that while riding in the current tension setting that I am happy with, when you hit a big bump the seat post does indeed absorb the bump with a click-like sound. Initially I found it a bit strange but got used to it. The suspension action, being a parallelogram arrangement, does not affect the riding position much, just like the Thudbuster.
I had some concerns that in dusty or other extreme conditions, the mechanical mechanism was somewhat exposed. For that reason I bought the neoprene cover that fits the seat post mechanism ((£3.02 + postage (reasonable) from
http://www.xxcycle.com/case-seatpost-suntour-ncx-sp-12,,en.php). So far it has worked well.
The seat post itself I found at Practical Cycles
but they appear to not stock them any more http://www.practicalcycles.com/userimages/procart77.htm. Rosebikes have them here at the time of writing at about what I paid ...
http://www.rosebikes.co.uk/article/suntour-seat-post-sp12-ncx/aid:614120All in all I like it, and the construction is solid. How it would fair on an extended tour I do not know yet. I have not seen any reviews on World cycle touring sites.
Hope that helps Matt
Cheers
Richard