I've been doing quite a bit of research on it and here's what I've found.
There are a ton of Paint Protection Films out there. They all seem to work well enough. I haven't heard of any major horror stories regarding them.
In the Greater Seattle Area, I've found that there is a wide range of prices for them. $400-900 US, for a full install (bumper, hood, grill, lights, front side fenders and mirrors).
There are a number of materials out there. A variety of 3M products and Llumar. Llumar is completely transparent, but is the newest of the films that I've found. 3M has also, apparently, changed their glue formula, so even though their product is semi-translucent, it's supposed to be better then it was. 3M products have been around longer, so more people install with them and they have a longer proven record.
I've settled on doing it two ways. Llumar on my lights, because of clarity, and X-pel on body parts, mostly because of cost. I've found a local semi-chain shop that offers a lifetime guarantee against peeling, yellowing and product defect. It also helps that the X-pel is 1/2 the cost, here.
Oh, I got some of the Llumar film from the guy who did my lights and decided to "play" around with it a little. I put a piece around the keyhole and the back hatch hand-latch. The keyhole bit, was fairly easy, minimal stretching. The back hatch hand-latch was a major pain in the ass, but I got it in. It was enough to teach me some about working with films and to know I want a pro to install my hood and bumper.