Cernd, because he doesn't improve. He's one of the earlier NPCs you get, so earlier in the game his werewolf and greater werewolf forms are actually good compared to Minsc or other tanks earlier in the game. But as everyone levels up his offensive capabilities never actually get better, while the other guys get better weapons, armor, etc. If you had to choose between him and Jahiera, Jahiera has better long term value.
HaerDalis, while also pathetic, is at least improvable (though not by much).
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