I have been using the Cane Creek Thudbuster suspension post for about a month now. Only one comment- I do not need a full suspension Tandem. We do ride the Tandem aggresively so any suspension post will go though it. Today we tackeled a high speed Downhill at speed and I managed to stay seated right the way down. No bottoming out, no sudden jolts of pain, and more important, no necessity to get out of the saddle.
I went for the 3" version and was wondering if this is too much movement. I thought that the 1.5" may have been more appropriate, but after the punishment we put it through today, I made the right choice.
I can see why they are a lot more expensive than other posts, but the money has been well spent