They are a nail-in heavy plastic bucket pocket. Compared to a Gold Crown, they are a bigger pocket, but because of the different shelf dimension and facing angle, they actually reject more balls, especially when shooting down the rail with speed. To give you an idea, I had a triple-shimmed GC1 that played PRETTY tight, but my Champ Pro is sometimes more frustrating to play on with just the factory shims.
A Pro-cut Diamond is going to play a bit more brutal still. The Diamond pocket system is superior to any other manufacturer out there though with the flush-mount leather pockets.
I hope I've answered your questinos. If you have any others, please let us know.