I find a slightly denser, synthetic brush is best to apply these. They sit between a powder and a cream and the texture can seem a little odd at first. My usual eye shadow brush (MAC 239) doesn't quite have the right texture of hairs to work best with these. Your (clean!) ring finger will work quite well too.
They do last all day on me with a primer with no fading or creasing. I haven't tested them to the full extent of 24 hours but they stood up well to the heat in Atlanta!