Well to me the big difference between TPM and Jedi is that in the latter, whole sections of the film are terrible and virtually without merit. You have the Vader/Palps/Luke stuff, which is great, and the space battle, but to me THAT'S IT (the Jabba's skiff barge thing has like 2 cool moments and about 20 bad ones) for the whole film.
In TPM, even a scene as bad as the dinner table at the Skywalker residence has some great lines, like Qui-Gon and "I wish that were true." Same with Otoh Gunga. Okay, there's a lot of Jar Jar, but the whole design of the underwater city is awesome. And I personally love Boss Nass. There aren't any SCENES that are worthless, with the exception of Jar Jar entering the droid hold on the Queen's ship (it's mercifully short). Now to be fair, there aren't many scenes that don't have something forehead-slappingly stupid in them, but it's more consistent and you don't have to wait as long for the next highlight.
TPM also benefits from seeing all these new characters and places for the first time. In Jedi the only character improved from the previous films is Luke, and that haircut threatens to sink him as well. As for "exciting" new settings, Jabba's palace is like a combination of the Jawa's Droid Factory and the creature cantina from A New Hope. The Death Star and Dagobah we've seen already (and more OF them the last time), and most of us have seen a forest before. In TPM you have the Federation Base Ship, the underwater city, Theed Palace, Mos Espa (a lot more varied than what we've seen before from Tattooine), and Coruscant. It's loaded with imaginative ideas, whereas in Jedi that's left to Jim Henson, and doesn't yield very good results.
