It's always amused me to note that, in general, the most egotistical people have the least reason to be so. I followed Prologue fairly closely prior to its release, and downloaded/watched it shortly thereafter. I found the experience to be more painful and cringe-worthy than sitting through the official PT itself.
As someone else mentioned, his visuals are fairly impressive, and one or two sequences are laudable. But the overall editing job is so poorly done, the entire thing just feels hacked-up and confusing. My wife (who isn't a hardcore Star Wars fan) sat through it with me, and couldn't follow the plot to save her life. We were especially taken aback by the train-wreck of an ending. It's like AntiMatter went so far with the project, decided "eh...that's good enough," and just released it unfinished.
The really hilarious part is that he doesn't even accomplish what he set out to do. One of the major objectives of this fanedit was to restore "saga secrecy," i.e. preserving Vader's secret identity. In the beginning of the edit, this purpose is served by deleting any reference to "Anakin" when Vader's dirty ROTS deeds are referred to. When he gets to the end of his edit (the Palpy-Mace-Anakin confrontation) AntiMatter is clearly out of ideas, so he slaps a two-second shot of Dooku showing up unexpectedly, and then ends the edit there, with no dénouement or closing sequence or anything, just a bad montage of a few random ROTS scenes. He explained on his site something to the effect of "now when you watch the OT, there's a 50-50 chance that Vader is either Anakin or Dooku." Which really doesn't make any sense at all. Even ignoring Dooku's advanced age in ROTS, the fact that he retained all the ROTS footage showing Obi-Wan and Padme discussing Anakin's (some unnamed person's) youngling killing spree and expressing disbelief/concern for Anakin (the mysterious stranger), pretty much rules out any reasonable person from concluding that Dooku did it (whom Obi-Wan and Padme neither know particular well nor care for).
In short: it's a garbled mess. It's kinda laughable that AntiMatter deemed it worthy for public release when it was obviously a rough draft, and a poor one at that; it's pathetic that the sycophants on his website rate it so glowingly; but it's just downright sad that the place has decided to define itself as a juvenile, anti-OT.com, anti-FE.org, den of self-congratulatory wankers.
