Unacceptable, after 3-4 washes the paint comes off, which takes hours to apply. The result is very mediocre

I don't understand what you expect a cream for 10 euros to do for you!! I was very satisfied with the result on the scooter's plastics! Okay, I don't know how long it will last, but the result is perfect! I don't think it's a hassle to apply it after 2 minutes of work!

I used it on two vehicles..
It is very good, the plastics changed a lot and the bumper too! It needs a good wash first, drying, and personally, I applied glass cleaner after washing.
Make sure to apply vertical strokes first and then horizontal ones for the result to come out correctly. Maybe in some areas, a third hand will be needed, do this by pressing firmly on the sponge

For easy and fast restoration of damaged plastics, this is the way to go.
It lasts at least 4 years, judging by the scratch in the photo that was taken in 2018.
Obviously, it requires excellent cleaning so that the surface is spotless before application. I used isopropyl alcohol in the final stage of cleaning.
For the lines it leaves on some, it is because the application is not uniform, which is perfectly normal if the hand is not accustomed. The solution is to pass the surface with a second, clean sponge to remove the streaks.
A better solution is to use bumper spray, but this requires more time, attention, and practice.
Plastic maintenance products do not help much as they are temporary solutions that simply cover the problem for as long as they last, and in most cases, they have a glossy finish, which personally I dislike when it comes to matte plastics.

I did three repetitions within approximately two months... even after one or two washes, it fades in certain areas and leaves gaps in the black like stains... it does what it promises only for a short period, no durability at all.

Really any simple black spray will have much longer durability, resistance over time, absorption, and will not leave any streaks if used correctly compared to Sonax! This product is useless! Very expensive, I have seen better shoe paint sponges than this one used by this particular product, zero resistance because after the first wash it lost 50% of its shine, while from the third wash onwards the plastic parts of the machine look as if they were never painted! Overall, if someone wants to waste money, time, and energy, this is the most suitable product, something that unfortunately Germany has accustomed us to in its products in recent years.

I bought the product and applied it on black plastic, like the part on the mirrors and columns. No matter where you apply it with this sponge it doesn't leave an even color, but leaves many streaks. It's not good, I regret it because it looks worse

I bought this product a few days ago!! Something happened to the plastic in the car, but then I applied it to my pig and it became a black carpet!!! The trunk became a thing full of splatters!!! From what I understood, if the surface you want to paint is strange, don't even buy it