Here and there, I catch clips of the Japanese edition "original" Pokemon anime, though it's a rarity. Just a few days ago, I saw clips involving Professor Ivy and Lorelei (GOSH SO HAWT, BOTH OF THEM :3).
I liked Ivy's seemingly respectful tone of voice. Misty was a bit annoying to listen to with her Japanese voice, and Ash sounded like his English voice actor was speaking Japanese, fitting for a shonen anime or something. XD While I'm used to Professor Oak's (old/pre-Jimmy Zoppi) voice, the Japanese voice actor was quite amusing to listen to.
All in all, the Japanese version of the anime seems OK, though I prefer the English voices better. Regarding edits/censorship? Japanese all of the way. I'm fine with "Americanizing" items and stuff; but I tend to dislike when dialogue is dramatically altered, or kanji or music is removed. Thankfully, The Pokemon Company International seems to be doing a much better adaptation/rendition of the anime than 4Kids, preserving a good majority of the original content. They're going as far as to even bring back the Who's That Pokemon? segment. :) Just needs a little work on the theme songs and we'll be fine... >.<