Thanks for the write up.
Those results aren't much (if any) different from a regular igloo/coleman/whatever with 70 degree temps and opening the cooler from my experience.
The biggest draw to these coolers (besides the fashion statement) is the ruggedness and ability to hold ice with the lid closed for days on end. They are just too heavy for everyday use when having to physically carry them camping and beach trips.
I've had my 26 qt all summer and just picked up a 52 but haven't had time to use the 52 yet. I can assure you the performance is much better than a standard Coleman/igloo cooler. I don think it's reasonable to actually expect the 8-9 days some of these coolers advertise though unless filling it 100% full of ice and having one tiny cube left is satisfactory to you (not really sure what the point of that is myself). It is nice to know you can go 2-3 days between topping off the ice rather than doing so every day in with a standard cooler the same conditions. Most of the camping I do is not convenient to have to get ice every day so these are worth it to me.
Just my .02