I don't believe REVENGE OF THE SITH was the best of the prequels by a long shot. You know what was...
THE PHANTOM MENACE. It's infamous in its reputation, but it's quite overstated. It might be boring, but it's nowhere near as overtly and abhorrently awful as the other two. Really, it's harmless. And because Lucas is actually using real sets, it feels like a genuine movie.
I disagree. MENACE has a couple of cool things about it (e.g. Darth Maul, and a coupla pretty good scenes on Tattooine), but it's still an awful, awful film, regardless of whether Lucas used real sets or not. It's boring, juvenile, tells a hopelessly muddled and fundamentally uninteresting story, and is totally devoid of any heart or flair. Charmless dreck, and by far the most childish of all the STAR WARS flicks (which is saying something).
The best of the prequels - and, incidentally, my favourite STAR WARS outing - is ATTACK OF THE CLONES. It's very, very flawed, of course, but boasts some fascinating characters and plot elements and some terrific design. What's more, it has a wonderfully epic feel, and I remember Harry Knowles making a good argument that it was actually very much like a Bond film in some ways.
I never cared much for SITH, though, although it's certainly a lot better than MENACE.