We have the 3M film on the front of the motorhome, the toad, and the other car at home. We love it! But it does have to be put on professionally or it will look terrible. Done properly you can't tell it's there and it's really saved our paint, especially on the motorhome. And, personally, it really looks nice when compared to the other methods. We had a black bra on the front of one motorhome and I grew to dislike it intensely because it was so ugly, but also because we had to remove it to get to the generator. We have a clear plexiglas shield for the front of the toad which we use when towing but I don't think they're being made anymore. We've kept the large rock guard that came with the motorhome and is located behind the rear tires. I think it helps keep rocks from being kicked up onto the toad, but that's my opinion and others may disagree.
As to the dirt that gets into everything, forget about trying to cover every nook and cranny. It can't be done! Look at it as your badge of having fun! One time we were at Canyon de Chelly ruins where we had to ford a stream. A month later we took the toad in for service at home and the technician asked Jerry where the sand came from on top of the skid plate. HA! That came all the way from Canyon de Chelly to Redwood City CA. We never worried about trying to take it off because it simply didn't matter. Every time we get home from a trip we find new dirt (often red from Utah's red rock country) and if it comes off, it comes off - if it doesn't, it doesn't.
ArdraF