I absolutely recommend it. The poor raptor has wide axles so any crap coming off the front tires will spray the entire side of your truck. The stone chips are a great accent too. There is another post on the forum (in the exterior mods section) that talks about the different styles. I went with the cheap ones that Birdman has on his truck. His photos are listed in that post.
I cant overstate how well the ones he purchased worked out for me. They look like they were made for the raptor so much so, that you dont even notice they are there.
Rather than using the mounting screws that came with them, I used plastic push pins (AKA Christmas Tree pins). They worked like a champ. I had to drill into the plastic on the rear wheel wells but not the metal fenders. In front, there was one spot where I needed to drill into the fenders but I dont think that will cause the front ones to rust.
I would really encourage you to look at Birdman's post. It didnt alter the look of my truck at all. They seem tough yet plyable. Plus they were inexpensive.
Good luck.