Pros: It's nice and cold.
Cons: It can make you sick.
I enjoyed 8 nice, cool months with the Chillow. Then, I noticed black mold on the white side of both of the Chillows. I applied a clorox solution to them and it disappeared, only to return days later. I contacted Chillow customer service, whose representative was lightening fast to tell me that mold is not covered under warranty. I threw away the 2 Chillows.
At a physician visit 2 weeks later, my doctor found an infection in my right ear (I had usually slept on my right side on the Chillow.) I told him my Chillow story and he said that it was the likely cause of my infection.