True, and I do love group quests and dungeons. The thing is, 'quest based level progression' usually means do quests solo until max level with the occasional group quest/dungeon tossed in.
The main point though, is that doing only quests for leveling is just as much a grind as killing mobs in a group, especially since most quests ask you to grind mobs ;)
Personally, I like as many options to level as possible so I can do something different every time I log in. Some days I don't have much time and feel like doing some solo quests, other days I have more time and feel like doing a dungeon or 2, and yet other days I need to blow off steam and just want to butcher gobbies all day long ;)
