The colour scheme and style are consistent throughout, and they look INCREDIBLY professional.
The characters are easily recognizable, and easily iconic enough to bring a smile to the fanboy in me.
I can't really find anything to fault.
While I may think that Heart Pieces don't look dissimilar to normal hearts, the lack of the familiar heart-piece outer line is necessary to fit with the other suit styles.
The shape is defiantly the same as the games though, so it works out noticeably enough after a moment of looking.
These are pretty much everything I could want from Zelda Cards.