It can be argued that summoner is easier for various reasons.
Really at 30 you cannot get a real idea of how a job is as it changes @ 50, and now 60 is even more different.
Summoner is the best at aoe damage (used to be blm) and has fairly good single target damage while having mobility. Black mage is just behind in the aoe department but has higher single target damage (your a turret really). but does not have the mobility aspect of every other job in this game