Artemis cushions, made in Germany, are installed by Gabriels and Diamond who make the best tables in Europe and North America. If it is good enough for them it is the best available.
Should last decades.
Just had one of our tables overhauled including installing Artemis. Cushions play great.
Much other stuff available from China is of unknown quality. Cheap now, but is it cheap if you have to replace it within five years? If you search around this site you will come across some horror stories.
My dad put Artemis on our home table about 20 years ago when he first heard about them. Still bounce like new. In my experience, they are the most consistent rubber.