Just watched Arsenal absolutely own Everton, and Edu looked very good in central midfield. Infact he was involved with a few goals, making sharp through balls into the feet of Bergkamp to set up some nice finishes. His passing skills are indeed very good, and he would certainly add something to the team. Not too sure about his tackling skills, however his positioning sense isn't bad at all. Another thing to watch out for on Edu is that he seems to hold onto the ball a bit too much sometimes in the middle of the park, however with the slower pace of Serie A that shouldn't be as much of a problem. But I would welcome him to Juventus to add some creativity to the midfield.
And Edu is not Arsenal's best midfielder. Vieira and Pires are better, no doubt. Talking in terms of central midfield Edu is behind Vieira and on par skill-wise with Gilberto.