I ordered two of these 4-inch memory foam pillows after reading the 6-inch thick (same) pillow reviews. There were no reviews on the 4-inch pillow that I ordered, but since the other pillow is the same, I thought I couldn't loose. I did not want it too thick so I would not get too much material around my face, and find it hard to breathe with memory foam around my face... I thought the 4-inch seemed perfect, but for me it seems too flat, but my husband likes it. I feel like I have to put my arm under my pillow for elevation when I side or side-stomach sleep, and I don't like thick pillows either. I am of average weight also. I may adjust, as I understand from the reviews I've read, that they do not let you return bedding. If I returned, I would definitely want the 6-inch, because it is such a good quality pillow. I just feel like I don't get the benefit of the memory foam, as it seems a little thin, seems like it is not quiet a 4-inch. If you like the thin version, go for it, but if you like at medium-thin to medium and up, then definitely go for the 6-inch. Otherwise this is a good pillow, and I am picky, but was so in hopes that this was the right thickness. It may be perfect for you though...I will continue to use, if I am not allowed to return for now.