The Viewtiful Joe anime is without a doubt the single greatest anime ever made, based on what was already the greatest game franchise ever made. It keeps the spirit of the games while changing the plot into a more streamlined narrative and follows up on some of the themes the games explore with how media and super hero stories can project passion and inspire others. It's a perfect anime, or at least the English version is.
The English version of the anime from Geneon has the talent of some of the best voice actors around and punches up the dialogue to make an already fairly self-aware and funny anime even funnier. This can probably be attributed to the dub being directed by Bob Bucholz, one of the most prominent English writers of the first two seasons of Digimon, as well as Duel Masters and Bobobo-Bo-Bo-Bobo, all shows that wouldn't be nearly as good without the English script.
While the English dub of the first half of the Viewtiful Joe anime doesn't change a lot, there were changes that had to be made because, like Digimon, it was on a Saturday morning broadcast, subjecting it to Broadcast, Standards and Practices, meaning things had to be adjusted to be allowed to air.