I never really understood why nearly everyone hates the prequels, but let's face it--there's a lot of good things about it, too.
1. The lightsaber battles definitely got better when the prequels were made.
2. We see Jar Jar less in each movie. In I, he's a major character. In II, he appears occasionally. In III, he's just an extra in one scene!
3. Yoda only shows an excerpt of his Force abilities in V, but it's not until the prequel trilogy that his powers burst out in full flower.
4. For a series so low on humor, some scenes are surprisingly amusing, like when Obi-Wan plays a mind trick on a death-stick seller, when Jar Jar gets tangled in the battle droids wiring and (accidentally!) takes out a droideka, or the phrase, "I don't care what universe you're from. That's gotta hurt!"
5. Hayden Christensen has at least some quality. Even silently he demands a strong presence, and in the end he forms a perfect connection with Jake Lloyd and David Prowse.
6. The opening of III--you don't have to sit through all the talking to see one of the most epic battles of all.
7. Ewan McGregor has really turned Alec Guiness into a real character. As you see Obi-Wan age throughout the movie, Ewan and Alec really connect his life and legend.
8. Unlike the original trilogy, you see a planet from multiple angles and perspectives.
9. Almost all your big questions about the Star Wars galaxy are answered here as it widens the spotlight--Obi-Wan's past, the full story of Luke's father's fall to darkness, why the Jedi are "all but extinct."