I have used the DJI guards, and have also flown without any guards, and now with these Bestem guards.These guards seem to affect flight less than the DJI guards, but they still do affect flight. That's unavoidable.These guards sit a little lower, further from the blades than the DJI guards, and so they do get further into your video frame when under heavy forward acceleration.The DJI and the Bestem mounting screws are the same weight (0.2 oz) more or less. My scale only records in .05 increments.The Bestem guards, including the mounting screws, weigh 2.95 oz.The DJI guards weigh 3.3 oz including screws.Update: The SummitLink guards use all four motor mounts. The screws alone are 0.6 oz. The entire set is 5.6 oz - nearly twice as heavy as the DJI guards.The Bestem screws do not come with loctite on them, I had to add that myself.The Allen key size for the Bestem screws is the same as the DJI screws, and the stock motor screws.I checked how far the screws protrude from the guard mounts. It is the same distance as the DJI screws protrude through the DJI guards.The package included some shorter screws as well. Not sure why, they are longer than the "short screws" you use when you don't have any guards connected, and the wrong shape as well, so I can't see a scenario where I would use them. And there was no manual or other instruction with the kit.The guards are made of a thinner, more flexible plastic than the DJI guards, which makes them lighter and less likely to snap, but also means they can give way and let things contact the props.The guard mounts have unnecessary extra material sticking out beyond the arm, which makes it not fit in the hardshell backpack without carving out the foam. I did carve out the foam and they fit OK now.The guard does not extend as far beyond prop blade as the DJI guards, making it more vulnerable if the prop guard gives way a little, which it is likely to do, since these guards are more flexible than the DJI guards.The guard does not precisely follow the curve of the the prop blade, so the blade actually extends beyond the guard on each side of the guard. This also makes the props a little more vulnerable. If you get something between the guards, it can contact the blades. This happened to me on my first test flight, with a rope swing I didn't manage to avoid.When I crashed from about 6 feet in the air, one of the prop guards popped out of its clip, but nothing broke. That seems reasonably good to me. When these prop guards break, I will probably go ahead and try the SummitLink brand rather than buying another set of these.Update: Crashed again due to guards not completely covering the props, and this time one of them broke. It did not just crack, it shattered. A piece of it is missing. I'm tossing these in the trash and trying to SummitLink ones instead.