Bard - Most mobile class. Can continue to DPS while moving. Most 8 mans will have at least one Bard for their songs. In addition, some of the better statics use multiple bards on End Game content due to the zero down time they have. Excel at mobile fights, less impressive in stand and fight encounters. Require's a lot of attention. Combat style includes song to buff, multiple instant cast abilities, and several dots.

Black Mage - Turret dd. Suffers most from movement. Highest AoE damage in the game - second lowest potential single damage dd (Potentially lowest, if a Bard and Dragoon are present). Combat style based on switching between high damage moves that reduce mp regeneration, and low damage moves that increase mp regeneration, all the while using lower level spells to get ability procs for higher level spells. Can be played while asleep.

Summoner - Dot class. Does not suffer much from movement based fights. Between highest and second highest damage potential, depending on battle mechanics. Damage increases as mob population increases. Pet class - can Tank/OT easier content. Jack of all Trades class - can tank (Titan-Egi pet), heal, and combat raise (Including swiftcast raise). Lowest HP of all classes, combined with troublesome MP management if DoTs have to be applied to multiple targets in quick succession (Ifrit Extreme being an example). Combat style revolves around keeping multiple dots up on enemies, multi-targeting when possible, managing pet location and skill usage, using Aetherflow stacks to access powerful skills (Obtained by using Aetherflow, a once a minute skill), and adding healers by assisting in spot healing when necessary, and raising party memebers when healers are too stressed to do so themselves. The amount of attention one has to pay is largely based on party skill - A skilled party means a summoner only has to dd, which can be done while watching movies or talking on the phone. As the skill of the party declines, the summoners work load increases, particularly when it comes to raising.

Basically, Bard are required and pretty fun, Black mage can be fun, but boring, and Summoner will make you smile when it comes to damage, but it will make you absolutely despise the perma-dead Dragoon and over worked White Mages.