What are the best evaporative cooler pads to use - aspen or the new dura cool or cellulose pads?

Ok, you Arizona people. It is time to do the cooler. Every year in Tucson, I go get the Aspen pads from Miracle Cool on Miracle Mile. A neighbor suggested the roll of blue pads and I have seen paper ones - I think they are green cellulose. Any opinions on what works best?|||I'm not from Arizona. I'm from New Mexico but we also use evaporative coolers. I like the thick aspen pads. I have tried the blue pads and didn't feel they lasted as long as the aspen nor did they do as good a job holding the water, thus cooling the air. I have not tried the green pads. If you can't find the thicker aspen pads, you can always double up to get thicker pads. Another trick I have used is to add a second pump and spider so there is more water to the pads. This definitely cools better.|||I like the blue ones, smell better than the aspen pads. Seem to hold the water better, too.