I play bass and due to the heavy gauge of the strings, the pick used to rotate. This obviously causes a lot of problems.
Enter Dava. What I like is not just that they don't slip, the way this pick is made, it bends quite a lot depending on where you hold the pick.
This is great, because the bend gives it a sticky feeling that you can only get when you play with your fingers but at the same time, it gives it the "ping" you can only get with a pick.
I know many people scoff at pick players and I used to do the same but playing with a pick on my fretless F bass has helped me intonate correctly due to the "ping" I can get from the picks.
After using this pick, I have not had to cross shop at all. There are different types of Dava but as long as you get the ones covered in black rubber, they all do the same. Some give more ping, others sound a little more fuller. But it's very subtle. The biggest difference is in the feel of the tip.