I'm a 60-year-old woman with osteoarthritis in my neck. I sleep on my side.
The "patented interlocking fill"? Imagine breaking up the solid foam of a bargain-basement pillow into irregular 2x2-inch chunks and refilling the original pillow cover. The recommended firmness ("White" for my "My Pillow") is a factor of the ratio of number of foam chunks to finished pillow size. The product as shipped is greatly compressed and lumpy. I "plumped it up" in the dryer, as instructed. It was less compressed but still noticeably lumpy.
After one uncomfortable night's sleep, I detected no difference in body-heat transfer/retention and head/neck between a solid foam pillow and "My Pillow." The foam chunks were still lumpy, causing additional discomfort.
I rejected the replacement offer and returned "My Pillow" for a full refund. I do not recommend this pillow.
Reviewer is in unhappy mood. Please immediately contact the author of this review to discuss bad quality of mypillow pillow. Mypillow needs to read this review and look into the issue (if any) according to poster's claims.