AM, TMK, ND: All provide the same type of girl-friend experience. This usually includes full-service along with certain options for each girl. If want to do something specific, you should ask to see who does it. For example, most of the Japanese girls won't do anal or other risky stuff.
Club Boo charges an extra premium or 'tip' to get full-service or other extras.
Manami's looks: Better in person, I think. Her eyes are hidden in the pictures and I think that completes the whole package. She certainly has the best service attitude since she takes what she does very seriously. As for who can compete with her, that still has yet to be seen. There was another recent review of an AM girl that reportedly could outperform Manami, but I don't remember off-hand who that was. I think JimN posted that review.
For the conversational piece: Asuka and Manami are still hands down the best ladies for talking to.