It works very very well.
My headlights were pretty hazy too. I sanded it with 1500 grit and then 2000 grit and the headlights felt smooth again. Then applied a couple applications of plastX and it looked like new.
You gotta work the polish into the scratches and it will fill up nicely.
Got very surprising results from just polishing it without sanding, but still looked bumpy up close so I went ahead and sanded it.