the viewing area is in the "rose garden" area slightly to the right of the hub. You are a little off center below the zip line for Tink to fly.
We used one of our fast passes there one night as we arrived late and I knew the kids would want to see the fireworks.
It is a nice grassy area not crowded at all on our particular night.
We brought our own dessert and a blanket (the grass was a bit wet) sat and watched the castle projection show (not nearly as impressive from the side as from the front...but nice).
Most people around us were far enough as to not block our view as we were sitting...though I don't know if that would always be the case.
I thought it was nice...we arrived 10 minutes or so before the projection show...