I've watch this special almost 5 years ago. I thought it was okay in my opinion. I didn't mind the voice actors change, I thought they sounded similar to the original, with the exception of Ash, he didn't sound like the same.
I did like this special. I liked the ideas of mirage pokemons, it was okay. But I wonder if we'll see Dr. Yung again after this. Probably not. And what about the Mew in this special?