all boiles down to what you want to play.  it sounds to me like you enjoy shadow more, so go shadow.  I only voted moon, so you can make me gear :).  but we always seem to get the job done with the people we have.  I think at 70, shodow is a more viable build than in the past, as the passive healing is nice, especialy as most of us preists are healing, adn we will be doing 25 man, so really only need 3 preists, adn if you are shadow to be backup heal I think we will be ok.