If you're not getting good performances from Benayoun you're doing something wrong. He plays great in lots of roles and lots of positions.
As for Aquiliani, his stats improve a ton. If not, again, you're doing something wrong. I dont want to to give away potential ratings to people who don't want to see them, but suffice to say that using FMRTE, Aquilani has a monster potential ability rating. Either way, his stats when you start the game are **** good. He has virtually no weaknesses (other than his heading) and plays perfectly next to Mascherano. Play Aquilani as a Deep Playmaker and Masch as an Anchor man or DM. If you're playing them side by side in the midfield, play Aquilani as the deep playmaker still, but play Masch as a ball winning midfielder.
Another thing that bothers me is I see every Liverpool story selling Fabio Aurelio right away. You'd be hard pressed to do better than Aurelio.