Seems decent. Only 2008 was pretty bad. It's obvious how 2011 was a poor year for him, and only his final indoor run managed to keep him in top 4. However, 2008 is somewhat surprising. I guess the four or five losses to Nadal don't help, but only three wins? 1 against Djokovic in MC, one against Murray at USO and one against Djokovic at USO.
What you see though is that Fed is not necessarily better than Murray or Djokovic in their matches against each other, but he IS way better in winning the matches he should win. He doesn't lose to Kohlschreiber (FO 09), Cilic (USO09), Rosol (W12) or Wawrinka (USO10) in a Slam. He just doesnt. Not even talking about losing to clowns like Verdasco, Young, Bogomolov, Chardy or Querrey.