I had one for my old car. It looked cool, but it destroyed the paint. I even followed the warnings that came with it saying you have to take it off if it gets wet, but the paint still got cloudy. I kept it as clean too, but it still wore through the paint at rubbing points and it was the OEM one and fit nice and tight. It did more damage than good.
I will never use one again.
I've got the plastic hood protector on my Baja. It's made well. There are special stickers and rubber bumpers that come with it to keep it from rubbing and hurting the paint.