I have the WeatherTech "Stone & Bug Deflector"
they also have a 'hood protector' but that's more of a flush fitting skin for the front part of the hood. The deflector installed pretty easily, they claim it's no-drill but it comes with two screws for the center (and I ended up using them, they drill into the bracing piece glued to the bottom of the hood) and clamps for the ends. The fit is pretty good and there is about a 1/2" gap between the deflector and the hood surface to smoosh a wash rag into when giving baths. Oh, forget about easy removal for waxing
Also if you are leery about drilling a couple of holes in your hood as I was - the hood is aluminum on the Colorado so rust isn't an issue.
I got mine to minimize the stone chips I've been getting on the front of the hood (the 'protector' would have been best for this), but I opted for the deflector as I can clean easily under it. As for actually deflecting anything I have NEVER found any evidence to support that statement and honestly a simple before and after smoke flow test in a wind tunnel would be pretty easy for them to do. Some manufacturers used to claim they increased mileage but thats a bunch of hooey also as the cars are designed with air flow in mind and the deflectors actually create turbulence - again there is a noticeable lack of video proof.
I also have their spash guards and they are actually no-drill