I originally bought one of these pillows many years ago on the advice of my chiropractor. It eventually wore out and I was in a hurry so I just bought a conventional pillow at a local store. I went through several regular pillows and still I was having neck problems. I finally pulled the trigger on a new Tempurpedic contoured pillow and the very next morning my neck felt better than it had in years. I mostly sleep on my sides but sometimes flip to my back. Works well in all positions.
You should know this pillow is small. The size is only based on thickness. Length wise the pillow is very small. At first the pillow helped me but within a couple of weeks it was causing more neck pain than I had before. I found out this was because when I'm sleeping I change positions. If you don't stay in a perfect posture this pillow will not work for you.
This pillow is hard and your head will not sink in like memory foam. I'm a side sleeper and my ear hurts when I tried this pillow. No returns or exchanges for a softer pillow allowed either. Also, the larger contour is too large and the smaller one is too small. All around poor design, and the pillow has not gotten any softer with regular use.
I bought this pillow to replace my 10+ years old original Tempurpedic pillow, which I believe back in the day came in only one size. I was so glad to have chosen the small size. The shorter side I can combine with an old favorite feather pillow; the taller side I can use alone. This new pillow is a lot stiffer than the original, has much less "give." The first time I slept on it, it felt like a rock. I have become used to it now, and keep changing sides as needed. I do miss the "squishier" original Tempur material, and that is the reason I give it 4 stars, not 5. (It could well be that it's the same material, only that as mine aged it became softer--I don't know. I hope so!)