Go with the Tundra. I picked one up this year. A total river running cooler. Spent six days on the San Juan with only six frozen water bottles in 100 degree temps and everything was still cold on the last day. It was the 100 qt. cooler.
I second the Tundra. With the o-ring seal I had 2 frozen milk jugs as ice on a five day trip this spring and the ice barely melted. Plus the o-ring makes it flip proof as no river water will infiltrate the cooler.