Can I be honest with you? Please don't take this a bad way. My immediate reply after seeing the picture was:
"What? Another new custom deck?"
I have to hand Ellusionist credit. They managed to do to playing cards what Pokemon did to baseball cards. They created this fad within our industry where magicians are willing to pay top dollar for 52 pieces of paper with fancy or unusual designs on the backs.
Honestly six years ago I would have lambasted anyone for using a custom deck or supporting this movement, but I've recently come to realize that cards are just tools of our trade. As such certain decks in the hands of certain people with defined characters begin to complement the overall image, and complete the experience. So I've retracted a lot of my negative comments in favor of a more individually based critique. There certainly is good enough reason to use custom decks so long as you can find the right one that works for you.
I digress. Since I don't really think you can do anything more to the cards to make them perform better than anything else out there, and since Vipers and Tally's are pretty much agreed to be top of the line as for decks being concerned, it comes down to a matter of personal choice. They look pretty. Not a deck I personally would use, but the Ace has an unusual font, and the card faces have an unusual pip arrangement. This does make them stand out from most of the other custom work out there.
All the best to you with these! I hope you sell lots of them.