Hayden was pretty okay in The Revenge of the Sith. Not so much in Attack of the Clones.

Clones is by far my least favorite Star Wars film, but I still thought the prequels were decent and never got why people are so offended by them. Yeah, the dialogue is pretty bad, but dear God, is Ewan McGregor just amazing as Obi-Wan. The prequels are seriously worth watching even if it's just for him - he's having so much fun with the character and really carries the movies despite their shortcomings.