Don't let the "keyboard/mouse vs controller" thing put you off. It doesn't matter if you're a competent player. As for what Job to choose, just play what you ENJOY. Don't play a Job just because it's "in high demand". This game is casual enough to where you can gear up any Job without too much trouble and still enjoy it. Make the game something you enjoy playing, rather than a chore. Plus, you can always gear up a secondary Job!