I purchased the black quarter socks a few years ago. I've really enjoyed them and they are very comfortable. I decided to buy more and recently purchased the white ones. The quality is still good, but the white socks aren't really white. They're more of a dirty white. I defiitely won't be buying the white ones again.
You can't quite tell the off-white in the pictures, but you can tell how visible the really off-white spandex shows through is at the back of the socks.