First of all - the place is under renovation right now - so depending on when you are going, it might not even be open. Second, when it does open, it will be different than it was - so in some sense, any reviews of it's past incarnation may be irrelevant.
Having said that, we weren't overly thrilled. The prices were fairly steep. I've been to better Japanese steakhouses in other places around the US. To be honest, I'm not a huge fan of them in general, but if you get a good quantity of food for the money they are fun. I prefer my sushi straight up (sushi's usually an afterthought at the steakhouses) - and prefer watching the skills of a good sushi chef over someone who can crack an egg over a spatula or flip a shrimp tail. (i.e. the quality of the food matters more to me than gimmicks and showmanship)
But if you don't have a good Japanese steakhouse nearby, then the one at Epcot is worth seeing. If nothing else, I think every American should at least get a hint of how others eat - like seaweed salad. I'm all for opening our minds to the rest of the world. Sometimes Americans are good about witnessing other cultures, and sometimes we're really narrow minded.
As far as the DIS, restaurant reviews sort of tend to cycle...sometimes a place is up and gets overly hyped, then folks who read the hype come back and say it wasn't all that, and how they hated the place...then it gets forgotten for a bit...then it gets hyped again (maybe). Sometimes places at WDW get new executive chefs, so that can impact a place - and it's reviews.(also the
DDP, and the new healthy choice directive). Take any review with a grain of salt.