I will put on my flameproof suit and be ready to be yelled at for this: I was totally underwhelmed by Fantasmic. I read so much about it and how great it was, but I thought it was just ok.
They show cartoons on a spray of water.

There is more to it than that, but certainly not worth spending 2 or more hours of my time to see it. Notice I said my time, not yours.

Most people here seem to love it.
I think we will skip it this year and do rides and get out of the park before the crowds.