I've done a few of these overlays. 2 flash gordons last winter then I did a xenon this past summer.
The one you have is similar to the xenon I did. (Got them all from classic arcades)
The whites are not very opaque. I had to paint all the white to make it look nice

The flash gordons I ordered within a couple months of eachother. The first was a thinner vinyl that was a pain for bubbles and stretching.
The 2nd one was a thicker material that performed much better.

I suppose I see why people don't like overlays. The quality is inconsistent. But, I suppose it's better than having no option at all.

Wish overlays were available for more games.... Sometimes it just doesn't make sense to stick in an 800 dollar CPR (if they ever make it) playfield into a $500 game.