yes. i hit 70 after about a weeks worth of playing every night. quests in outland get to the point where you're receiving 19k xp per quest, as are required to kill mobs of 30 things, so it's quick xp if you're partied up. being in a group is the key in outlands if you're looking for quick levels, then instances are not the way to go - quests are for sure.
but yeah, the guild i'm in is finally all attuned for karazhan, so we're going to begin it on sunday. i've ran it through once before though - it's tough.