After approximately 5,000 km driven (yes, I actually drove a daily car of the same km), Starline and DenBraven no longer functioned as fully as they did on the day of application. On the contrary, Turtle Wax and Motip still created nice droplets on my windshield, even at a speed slightly above 60 km/h (the aerodynamics of the car also depends here, more modern ones will have a higher speed).
What does this mean? If you want to pay extra for longer durability, choose one of the two mentioned products. Both Starline and DenBraven were easier to apply, but their staying power is simply weaker. Since there is not much difference in price, I will definitely invest in Turtle Wax or Motip in the future after a minute of preparation. And the answer from the title? They all still work, but the differences are noticeable.