She's a bit more popular on other boards, and to be fair Sheryl just doesn't cover /a/'s favorite fetishes like the other girls do.
Ranka is moe personified, and It would take a 4 page long list to describe all of the fetishes Klan Klein embodies.
Sheryl is a tsundere, but /a/ likes Alto as tsundere better. She's got a good body, but isn't as healthy as Nanase or Macro Klan Klein. She's got a strong willed personality, but isn't a warrior woman like K.K. or Carnelia.
I don't mind though. Less competition for Mai Waifu's affections.