I use a seat for my Mini-Max when day tripping but for most boating trips I just sit on my cooler with a Tuff River Stuff cooler pad on top.
I've tried the DRE/AAA style high back tubing seat and found it to restrict my movement in a way that was detrimental to being able to properly row. Maybe the tractor seats are better, but I'll stick to the low back.
I'm pretty sure a large reason this video turned out the way it did was because of the high back seat and not being able to make full strokes. The guy was set up well at the top but couldn't get full strokes in like the boat he followed...
I traded out with the guy rowing the boat that hit Bedrock later in the trip, and its was VERY frustrating getting it to move. I hear guys say they can get more leverage with the seat when rowing forward, but it doesn't allow you to use your body core (where most of the power is) to get real power when pulling. If you really need back support, like Trevko an MNichols, I've done the crazy creek thing in the past with great success. I've certainly had my fair share of back problems, but I've been very comfortable just sitting on the cooler with lots of freedom to move around rather then being trapped in a chair all day.
I've actually been thinking about making a cooler pad that has higher sides then the center so that it holds you in side to side. I find myself sliding sideways MUCH more often then I've ever slid forward or back.