Jumal's the best early in the game because his CA is much higher than Keepa's and he comes with Super Goalie (CA +0~10).

Further on you could pick up Miyu (Moonflow, North Warf). Her CA is better than Jumal's after Lv10.

Ultimately you want to get Nimrook. You can recruit him when you're on the (SPOILER)Airship, but he starts with a 28 game contract with the Al Bhed Psyches.