The DRE seat is junk in my opinion. I seem to have a knack for hitting the back of it with my elbows at inopportune times and the mesh on the seat portion of it slides back on the aluminum tubing and cuts into the back of your thighs. Good idea, bad design.
Sitting on a cooler all day is sure to give you a good case of "itchy butt" and a sore back.
Low back tractor seats offer a really good range of motion but lack a little in the back support dept.
The NRS high back is my new favorite. Very comfy for all day use.
I've never had a DRE seat upside down but I would imagine that it will be bent, broken or torn off the frame when the inevitable flip happens.
The NRS seats don't fare well upside down.