Feral is easiest to level. Ultimately it comes to down time, a feral druid has the least amount of down time between killing one unit and being ready to fight the next. Heal between pulls and regenerate mana while fighting in feral forms.
Balance is slow at the start but gets progressively faster in later levels, particularly once you are in Burning Crusade and higher content. However it does have significantly higher downtime than a Feral druid because you won't have your efficiency high enough until you are in max level gear.
Restoration will be slow to level no matter what simply because it takes you longer to kill things. They will have less down time than a balance druid however will take considerably longer to kill things so it is a trade off (have to drink less often, but take twice as long to kill something).
The biggest advantage to being a druid in general while leveling is your versatility allows you to solo many things that others can not. You are a hybrid that can do all functions, but unlike the only other hybrid that can do the same (the Paladin), you also have stealth which allows you to skip a lot of unnecessary stuff in order to complete your objectives faster.
Last edited by Quinafoi; 04-22-2010 at 09:38 AM.
"In anything, if you want to go from just a beginner to a pro, you need a montage." /w TankSpot WTB Montage for Raiders.