I don't think any of the PT films are necessarily bad. The Phantom Menace is rather dull at times, but if one manages to stay awake, it is refreshing to see a movie that takes its time to move at a more leisurely pace. I was watching the movie about two years back and I was surprised by the opulence of it all. When I saw Attack of the Clones in theaters, I found it to be an entertaining movie. With other viewings, it's revealed many of its flaws. And while I like it better than The Phantom Menace, I find it strangely more imperfect. I happen to love Revenge of the Sith. I love that mood of dread that's in the air throughout the film. It's like you're falling deeper and deeper into hell and no matter what you do, you can't get out of it. Unfortunately, it does make a fair share of missteps. The opening part of the film on the ship feels like a mess and other minor hiccups occur along the way, but in the end, I think it's a great film and a terrific addition to the series.
I love Star Wars and The Empire Strikes Back though I will confess that A New Hope feels a little duller than I remember it, but it's still a great film. Empire is my favorite and it always had. Return of the Jedi hasn't stood up well much in my opinion. As a kid, I was always turned off by Jabba and his pals, but it made for an enjoyable sequence. It's still entertaining, but it feels much lazier than ever before. In the end, the movie's biggest and perhaps its only strength is the Luke/Vader relationship.