I think Fed is serving better with the new stick......
But that's about all. Still a lot of shanking. I agree with Breakpoint, I think it's more his swing style...the way he takes the ball. On ground strokes it almost seems as if he's not swinging through all the way like he's afraid of the additional power or concerned he can't control it.
Of course this is on clay I'd like to see him on hard courts with it. What do you think. I just don't seem much of a difference in his game.