Depends on the situation. Sometimes I love going on my WHM, sometimes not. Basically, it comes down to if there's other good healers in the party. If I'm the only one, or there's only two total on team A or C, I don't really like it because I become the number one punching bag for up to 6-7 enemies.

For DPS, I've done bard, summoner and black mage. Hated black mage at first and thought I'd only ever go bard or summoner, but after trying black mage more, I love it. While summoner definitely has more instant cast spells, and the constant damage from the pets, the black mage has some interesting tools, especially tools for getting away and/or crowd control.