They are great. I have two Anafis so I got two sets, at different times from different sources at different prices. The guards themselves seem just the same! They feel very light and suggest that they would be brittle but I only use them for keeping vegetation out of the props or guarding against a grazing impact with a wall or to make the drone look less of a danger when flying near people or wildlife. They push fit over the legs and seem to grip on three sides. The best thing about them is how fast they can be added and taken off again. I have prop guards for the DJI Spark, three different kinds, and they are all less satisfactory than these for the Anafi because they take much longer to put on and take off. If prop guards take two or three minutes to put on and take off you will leave them on when you shouldn't or leave them off when you shouldn't. These take half a minute to snap on and off the full set.
I haven't tested them for impact on top speed and so on because I can't foresee any situations in which I would be using them and expecting to be flying far or fast. I think they have some effect. When hand launching the drone I suggest holding the drone out quite high because it tends to drop as it isn't anticipating as much weight, launch shoulder high rather than waist high. By the time it has dropped half a metre or so it compensates and will then hover as well as ever. It probably catches a little more wind and so will use more power. I recommend them heartily for those flights when they will be useful: when people might be watching you, when looking up at bridges and viaducts, when flying close to walls or when flying very low over vegetation you don't want to scythe away. They are not perfect. I have crashed into a twig with the prop guards on and ended up with a damaged prop anyway. I have also managed to behead one bluebell, but without them on I expect there would have been much more accidental damage.
The reason I bought them was following a crash at a viaduct, looking up at the arch, doing the Anafi's party-piece. I was manoeuvring very slowly and returning the gimbal to horizontal when the props clipped the wall causing the drone to drop about ten metres. Fortunately, it landed in long grass and the only damage was to one of the props. If it had prop guards on it would have just gently bounced off.
