I've said it many times before, and I'll say it again. TPm had the "magic feeling" of Star Wars, that the others in the PT lacked. It FELT like a Star Wars movie. We were in a Galaxy Far Far Away once again, foreign to us yet also familiar. The acting is amazing compared to the crapfest of Episode Two, and the "Duel of the Fates" kills "the Battle of the Heroes" in episode 3.
Something about that one was entertaining... I know people who fell asleep in the others. I know at least TPM could keep MY attention. ROTS I'd rather not sit through.