Wow... so much that I disagree with there Farlander. I'd respond, but 1) I'm too lazy and 2) it would be off topic anyway. Maybe you should transfer that post to a thread of its own; it would generate a lot of discussion I'm sure.
Back to the topic at hand... I actually thought TPM started off pretty good. We had a classic opening crawl, mysterious-looking Jedi in the cloaks, lightsabers cutting through blast doors... and then Obi-Wan and Qui Gon decided to run away at 80 kph. 'Huh, that's weird' I thought. But I let it slide. It wasn't until a few minutes later, when Jar Jar opened his mouth and spoke his first words, that I first began to sense that something was really "off". I thought, wow, that's just.... wrong. Really, really wrong. Why is a character talking like this in a Star Wars movie?
From there, the whole film snowballed into something that felt like it was 30% Star Wars goodness and 70% pig shit. On the one hand were things like R2, the pod race, Jedi council, and the lightsaber battle (all of which I liked), and on the other were such things as Jar Jar, "Yippee!", Boss Nass doing his impression of a motor boat (what IS that about anyway?!), the Three Stooges in space, a crappy-looking Yoda, and a lacklustre space/ground battle.
Yet despite all its shortcomings, I remember leaving my first viewing of TPM (I ultimately saw it five times in theatres) thinking "Wow, that was fun!" I kept replaying Duel of the Fates in my head, and vowed to go out and buy myself a lightsaber as soon as possible. Looking back, I think the few likeable parts of the movie, combined with the novelty of having a new Star Wars movie, temporarily masked the film's suckiness for me.
As for AOTC, I initially liked it more than TPM because I felt it had a more (and I use the term loosely here) "adult" feel to it... thanks, in large part, to being 99% Jar Jar free. Like TPM, it also had its good and bad: Jango Fett, the Slave 1, a rusty-looking 3PO, a bearded Obi-Wan, and Sand People being slaughtered were cool; a poorly-executed love story, 3PO's one-liners, Yoda fighting (a.k.a. "the green blender"), and robo-waitress were bad. Upon leaving the theatre, I knew right away that it wasn't great, but it was only recently that, looking back, I now see it as being worse in some ways than TPM in terms of pacing, story, and acting.
As for ROTS, I thought (and still think) that it's the best of the PT, and in some ways is even on par with ROTJ. But it, too, has its many failings: a cackling emperor, people dying from having no "will to live", newborns with a remarkable memory, robot slapstick, and wheezy cyborgs come to mind.
Ultimately, the PT, like all Star Wars, is fun to watch (to varying degrees), but unlike the OT there is no lasting appeal... I think RedLetterMedia does a pretty good job of explaining why this is. I think Lucas should admit he cocked up, hand over the reigns to someone who's still capable of making a film, and reboot the entire PT franchise.