Japanese is the best, no question about it. The voices are much better acted, and fit the characters well, the english is awful, not saying whats really happening and bull**** that isnt needed. Certain things are different because the english version was changed for kids who cant understand whats happening, like the androids were actually kidnapped as children and gero experimented on them and turned them into 17 and 18, thats why they rebelled against them, as soon as they got the chance. There are hundreds of little changes the english version made, it even changed the target audience, which was stupid. There is less blabbing in the jap version, all the flash backs and crap are usually added by funi, lets put it like this, one episode, super buu has just absorbed vegito, in english dub, he goes into a city and eats some cakes, in jap version he goes and destroys a city..... its crap like that that makes me hate the english anime.... ALL the annoying parts in the english version arent in the japanese version, plus there is swearing in the jap version (more realistic if your getting all your ribs broken your not likely to to say "ow! darn it!") Plus things arent cut, like when people get their limbs cut off, or broken, or decapitated, some of the just regular fighting is cut as well, i remember seing one fight between buu and gohan in english, and in jap, and the jap was faster and more flowing....
Of course non of them compare to the manga, because of the top notch illustration that toriyama maintains, it all look stunning, and there is more information and no stupid babble that isnt needed..... So i say Jap all the way, unless you have a problem with sub titles. The english version has butchered dbz, and given it a bad reputation.
BTW, Budokai was developed from the japanese version not funianimation... i dont like funi because they are a big company that dont care about their fans and just want money, thats why they dont put as much effort into communicating the story in the correct way, because they know that most of the western world regards anime as cartoons, and therefore they changed the target audience from 14-20 to 6-15.