It may not have been the best Star Wars movie, but it sure as hell was action-packed. We got a first-ever speeder chase, plus some Outlander Club action, a platform fight against Jango Fett plus a space chase, a Tusken camp slaughtering, droid factory raid, arena battle and follow-up battle, plus a 3-part lightsaber duel. Whoo! I don't think ROTS had that much action... or did it?
However, I will say that the worst acting I've seen in the entire saga is in ROTS, when Anakin plainly tells an unusually calm Windu that he's discovered Palpatine's a Sith Lord. The novelization does a better job of telling this scene, citing that Anakin's having a mental breakdown, plus that Windu begins to get all serious.