The biggest variable is whether you are being hit by melee attacks.  With a tank, or against a slow (think fireball) caster, balance will do much more dps.  However, spell pushback is deadly to a caster, so if you are soloing, you may have a hard time against mobs that use fast strikes and against hunters with pets.  With a tank, you still have to worry about aggro.  More often than not, a dps class (like a balance druid) will have more trouble keeping the damage down in a group than causing carnage.

In feral, your damage will be consistent regardless of how frequently you are hit because melee does not have any "pushback" type issues.  Also, if you pull aggro in a group, your talents and gear (feral talents with melee gear) will allow you to go bear to survive AND deal damage (I know, balance has teh armor bonus, but most instances are indoors and pushback gimps damage)