I just leveled from 70 with my Shadow Priest that had been in mothballs since BC and I did it almost entirely through LFD, doing quests while in Q. It might have been that I'd never done that before, but I found it fun AND fast, faster than questing to be honest. And I had always thought questing was faster. The only downside for me was now I have to go back and grind rep that I missed on the way up. I'm still finishing up Therazane because I need the shoulder enchant. Of course, killing stuff is EASY in Deepholm as a lvl 85 with an avg iLvl of 351...