I've found a good spot to try for if you're kind of late and it's only about 15-30 minutes before the show is Germany. Its view is more distant, but unobstructed. The drawback is after the show, you may as well bum around the open shops awhile afterwards. because you will be behind the crowds.
Do not watch from China or Morocco. The View is obstructed by the Islands. Also watch the trees no matter where you choose. They can obstruct the view of the skyrockets. This is particularly troublesome near the wheelchair access viewing area near Rose and Crown.
Look directly at the barges. Is the wind in your face? If so that's not a good area tonight. Of course if you're me, the wind shifts so as to be in my face all the way around the sucker. If I move, it moves right with me. Just like when I'm BBQing.