I love mine.
I'm now using prop guards almost all the time, where before I could never be bothered.
Very very easy to install and remove. Loved that I could order different colours without having to fart around with dying them or painting them. I could continue my black and red theme when I ordered them. Even the propellers now match them.
Can't say how tough they are, as I've still never crashed, not even bumped into something, but they clip on nice and tightly, and you'd have to hit something stupidly hard to dislodge them, and if you've hit that hard, I think your prop guards are the least of your worries. They certainly FEEL as if they'd be tough enough to handle the average stuff - tipover on landing, bump a tree/wall, etc.
And the huge advantage of course is how quick and easy they are to put on and take off. If the wind comes up and you want to remove them (these are less affected by wind than the bigger fatter DJI ones) you could come in to land, whip them off, and be back in the air in just moments.