I have some of the Malouf 600 thread count Egyptian cotton sheets that I use on my king-sized bed. I love them, because they are soft, durable, and of a medium weight. The weight falls between Malouf's light microfiber sheets and their heavy Portuguese flannel sheets. They are great for me, because I like a somewhat heavy sheet in the winter. The 400 thread count Egyptian cotton sheets are on my queen-sized bed right now. They are wonderful sheets as well. I wanted to explain the 600 thread count sheets to you so that I could point out the differences if you are trying to decide between the two. Whereas the 600 thread count sheets are a medium weight sheet, the 400 thread count sheets are what I would call a "light-to-medium" weight sheet. They are not as light as microfiber sheets, and not as heavy as the 600 thread count sheets. Because they have fewer threads than the 600 thread count sheets, they are more supple (the 600 thread count version is a little on the stiffer side).For this reason, I prefer the 600 thread count sheet during the cold winter months, and the 400 thread count sheet in the warmer months. If you tend to sleep hot, even during the winter, then the 400 thread count sheet would be preferable. Both are very high quality, soft, comfortable, and durable. I really like the gray color that we purchased as well. It has a soft, expensive look to it. I can recommend this sheet without reservation.