I'm in the camp where the prequel movies are a definite level or two below the original trilogy.

I enjoyed Attack of the Clones and Revenge of the Sith, especially with Christopher Lee's Count Dooku (I knew he wasn't going to survive it, but was still disappointed with his quick exit in the 3rd movie).

I didn't enjoy the Phantom Menace so much, and it was a disappointment watching it at the movie theaters. I didn't have a problem with the politics / trade etc, as feel they contributed to the overall story arc well, my main issues were Jar Jar Binks (annoyance, but I could live with), and especially Anakin - the plot just seemed to drag / become pointless / scarcely believable (in a Sci-fi / fantasy movie a funny point perhaps) whenever he was involved.

And this continued somewhat into the next two movies - not so unbelievable / pointless, but the whole romance arc between Anakin and Padme just didn't really seem to be well portrayed / that realistic, and his sudden switch and willingness to kill the child Jedi apprentices seemed to quick a shift in a very short amount of time (in the space of a couple of hours gone from trying to help the Jedi to committing a massacre - admittedly events in the second trilogy foreshadowed this somewhat but came across as just a convenient plot device than a realistic character progression). Overall a bit of a shame when such a key part of the overall story.

All in all they just didn't have quite the 'magic' of the original trilogy - I have re-watched both trilogies many times (mainly because my wife is a big fan of Ewan McGregor), but always enjoy the original series more.