In terms of prequel fanedits, my favourites have always been:

Magnoliafan’s Balance of the Force

Great restructure. All Gungan’s and Niemoidians are dubbed and some significant changes are shown through the subtitles, for example the Trade Federation casually discusses killing Naboo inhabitants, and the Gungans are looking for some kind of crystal the people of Naboo stole from them. Jar Jar is also this brash, Han Solo type, but without the cool factor, and improves tenfold. If you can get past the bad video quality and subtitles/strange languages, it’s great.

The Phantom Editor’s Attack of the Phantom

Little I can say about this one. All changes are well thought out and imrpove the story. I highly recommend the editors commentary if you choose to watch it a second time.

Kerr’s Dark Force Rising

Very short version of Episode III, cutting out a ton of my problems with the film. Grievous is actually pretty cool, and the pacing is great in it. No scene is useless.

I’ve never been a fan of L8wrtr’s or HAL9000’s versions, as they don’t do much to change the film and I essentially feel like I’m watching the original (though this reality is frequently broken by L8wrtr’s version with their poor audio cuts). Magnoliafan’s The Clone War is quite good, though he really doesn’t cut much from the film.