I love packet effects so when I saw this I had to get it. I was surprised though by how good a reaction it would receive.
I have made up two sets from the cards which were supplied and use both. I've kept the card blank rather than writing on them as this suits my patter and that version works well. Better is the version where the cards change to queens and then kings. Somehow, that latter one seems more impossible. I like using both though.
Overall, this is a neat little effect - but make sure you move straight on to another effect afterwards as this is one the spectators will ask to see the cards. You need to put them away and move straight into something else to deflect that. I slot the cards back in their wallet as I deliver the final line "so I guess I'm never going to be able to show you that trick after all" as the excuse for putting them away - the trick doesn't exist, according to the patter.