Two class players. Cesc has more to his game but saying that Aquilani is quality in what he does. Plus Cesc has played in more bigger games and has more experience than Aquilani despite being younger. Two great footballers.
on a serious note, I haven't seen Aquilani much but I can easily say that his shooting technique is way better than Fabregas. Fabregas cannot shoot a shot like Aquilani's one against Madrid. Also if it had been Aquilani in San Siro, I am sure the ball would've smashed the top right corner rather bouncing before hitting the net
I feel currently Fabregas is the better player. Stronger technically then Aquilani but Aquilani poses more of a threat from his set pieces. Aqui is quicker then Cesc but Cesc is a harder runner and better at holding up the ball.
Cesc is the better playmaker. His overall vision and understanding of the game is better then Aqui.