I can understand a sleeve making the toy easier to clean, but I wouldn't pay upwards of $30-40 just for that... and I really can't imagine the texture of a sleeve making much of a difference, when the vibrations are so powerful. They might be nice on a less powerful vibe, but I really doubt I'd even notice with the Hitachi. Maybe that's just me, but strong vibrations do a lot more for me than texture.
Could anyone who has one of these textured attachments comment on how much of a difference it makes? I'm really curious!