I then wound up buying a Crazy Creek Canoe Chair III which is very supportive, comfortable, and light---quite superior in every way to the Sitbacker.
I would not recommend the seat to anyone with relatively narrow shoulders. If you, like me, spend more than three or so hours in the seat of the canoe, then the Sitbacker is going to be butt numbing. Overall, the seat is O.K., but surely someone can do it better. Think I'll try a Crazy Creek when/if I get the funds.
Although the seat bottom padding is thick, it is a bit hard. The Sitbacker is also heavier and more work to portage than my other seats. This was partly because the portage yoke systems that I have fitted to my canoes required the Sitbacker to be removed. Ditto for car topping. My other seats can be left in place. It is certainly strong with a good range of back adjustment and high marks for all around, day long comfort. For a larger person who is not going to portage much, this would be a wonderful seat at a good price, a "10" for certain. I only wish it worked better for me.