Tillers: Easy, fast and fun
Anglers: Most of these quest are nice, the best way to lvl fishing
Klaxxi: Buff are fun but it's still the one I like the least
Golden Lotus: A lot of quest most of them a little too gridy
Cloud serpent: The first few quest are boring but when you get to the race it got better
BTW: questing as a disc priest slaying quests are longer