I have had film applied to the last five cars I've purchased. The first two I didn't do any research and had it applied as a kit at a tinting shop. After seeing how much it saved the finish I was sold. The only problem was that since it was a precut kit install, the fit was pretty bad and I had only done part way up the hood so there was a line where the film ended. The last several cars have had the full hood wrapped. By wrapped, I mean they apply the film over the whole body panel and wrap it onto the back a bit. This makes for the cleanest looking install in my opinion. It is also the most expensive and hardest to find good installers for. The best scenario is to cover the car with as few miles on it as possible.
As for films, my preference is Nano Fusion. I like how it matches the sheen of the adjoining paint. Some films make the paint look like it is not very smooth and somewhat dull. My Roadster came to me with Tesla's paint armor, which kept the chips to a minimum, but did not look great. I had the whole front and mirrors redone in Nano Fusion. I also had the chin spoiler done in a mat finish film. Both came out looking great. I could show you pics, but you can't tell anything was done, it looks like the paint. I wish the door sills had been done when it was new. They were in bad condition by the time I got the car. Film would have helped this I think.