Well, I would rather waste an hour on quest then three hours+. Using a guide is efficient, saves you time and stress, yet it takes the feeling of accomplishment out of completing the quest(or maybe it doesn't). I would imagine a good portion of people only do quests to unlock a new item or monster, i.e. summer's end for corp beast, now if you do a quest with that mindset then what's the point of not using a guide?