The ball are definitely premium and well deserving of their superb reputation. They have a nice feel and a consistent bounce. I usually play between 90-120 minutes and the balls did not show much degradation during that time period.
When I open other cans of balls there is a nice hiss when the can is depressurized. I was surprised when the sound emitted by the Diadem can when opened was more like an explosion than a hiss. The sound startled me and my hitting partner.
Lastly, I am not sure what happened to the case or box housing the 24 cans because it arrived in terrible condition. The box was ripped, torn and tattered badly and a lot of tape was used to make sure the box held together. Not a good look and not sure what happened there. But at least the case contained all 24 cans and the cans appear to be fine.