As "JustCantWait" says, I think you should go and judge for yourself, especially if you are on the dining plan. We've been to H&V and thought it was OK. Not the best we've had, but not the worse either.
My observatons here on the boards is that buffets and family style meals typically get lower reviews than other places. They especially seem to get detailed analysis on the reviews too (like "yuk").
Personally, we never miss Chef Mickey's, Liberty Tree Tavern or Ohana (Buffet and Family style) and would say that Sci-Fi and Coral Reef are the 2 worst meals we've had at WDW. Pick any restaurant on property and you will get mixed reviews.
We are going to Mama Melrose's for our first Fantasmic package, haven't been there and have read plenty of negative reviews. We still want to try it for ourselves.
Go and have fun!