While Ray of Enfeeblement isn't great, the wizard in my campaign has used it fairly effectively. While Hold Person is better at the same level (and the wizard has this as well), it's highly restrictive in what it can effect, whereas RoE works against anything that uses Strength to attack.
Even a single round (since the save doesn't kick in until the end of the target's next turn) of half damage from a big bruiser (which generally have a low AC and lots of HPs, making them fairly easy to hit with the initial ray) can make a huge difference. The party just hit 7th level, so I'm sure it will lose effectiveness as they continue to level up, but so far its kept multiple PCs up in situations where the baddy would have turned them into paste.
Even a single round (since the save doesn't kick in until the end of the target's next turn) of half damage from a big bruiser (which generally have a low AC and lots of HPs, making them fairly easy to hit with the initial ray) can make a huge difference. The party just hit 7th level, so I'm sure it will lose effectiveness as they continue to level up, but so far its kept multiple PCs up in situations where the baddy would have turned them into paste.