The Channel 7 commentators are appalling, but Jim Courier is pretty good. You just know he wants to facepalm every time Bruce McAvaney says something stupid, but he usually turns it around pretty smoothly and provides insightful commentary. He has a nice voice, too.
It'll be good when Lleyton retires and joins the commentary team, he makes a great commentator also. Listening to Lleyton and Jim commentate a match would be a pleasant experience, unlike listening to Rennae Stubbs and Sam Smith.