Me!
I think the DeSoto coolers are more effective through a small range of temperature and humidity, but they're shaped so oddly (they're basically a truncated cone with no tailoring at all and almost no stretch, so the opening at the top is bigger than the bicep) that they just don't stay up.
I've had good luck with the Zoot coolers this year, although with my injury I've worn them much more for sedentary outdoor events than for running. I have run in them a few times - short distances but hot enough temperatures to know whether they work, and they do.