I suppose it does depend on the type of game you're used to playing. I've watched a review from one of the site I usually trust, and they said it was so hard they almost gave up, so I didn't know what to think anymore.
Have you tried the patch to see what changes they made? (is it even out?)
Kinnikuman Nisei is almost entirely translated by Viz Media, but you would have to purchase the volumes if you would like to read it. If you're interested in watching Ultimate Muscle again, here's a link: http://www.youtube.com/user/epserbaddazz2#p/u
I haven't seen/read all of Kinnikuman Nisei (known as Ultimate Muscle in North America and the UK), but it was indeed very enjoyable. Even though 4Kids usually does horrible dubs, I found the jokes and sense of humor they implemented into the dialogue to be entertaining. I think you're going to really like the Mask family, partly because they're from England .