I had prop guards on my Phantom 1's. It seemed like a good idea at the time. And honestly, they DID save my bird on a couple occasions. One time I actually flew THROUGH a tree! The bird didn't skip a beat! It's kind of amazing.
On another occasion I was shooting a car lot. I had my FPV goggles on. I was doing a very slow dolly shot to the left when all of the sudden the bird stopped dollying left. I took of my goggles, and I had run into a pole. At 1 mph, the bird just bumped into the pole and just sort of stayed there. I don't have to tell you that had the prop guards not been there, the bird would've crashed instantly. After that incident, I learned to utilize a V.O.
Years later I do mostly mapping and Traffic Analysis jobs. I got rid of the prop guards years ago. But during those early years, I was glad to have them.
D