Should Magicians Use Themed Cards?
When Ellusionist released the first Black Tiger and Ghost themed decks some years back, I loved the edgy look of the cards as well as their quality and feel. 
However, at the time, I was apprehensive about performing with cards that were not standard Bicycle cards. My initial fear was that spectators may think that the unusual looking cards were gimmicked or trick cards.
But after several years of popular cards in all sorts of colors and designs, most of them manufactured by the U.S. Playing Card Company that produces Bicycle, Bee, Aviator and all the popular brands, I think that magicians are now free to use whatever cards they wish.
Spectators are accustomed to seeing different back designs and some designs can lend to a magician's persona. In particular, I think the cards are fantastic for extreme card manipulation (XCM) and card flourishes as popularized by Jerry Cestkowski and Dan and Dave Buck.
Arcane, the newest theme cards to hit the market, come from Ellusionist. The edgy-looking and attractive cards come in both black and white versions. 
I like the reverse exposure face cards, the slightly thinner and quality card stock, the gradient indexes that feature a slight fade out and ultra smooth finish that makes fanning smooth as silk. Like the Black Tiger and Ghost Decks, the Arcane decks are manufactured by the U.S. Playing Company for Ellusionist.
I also like another new and edgy deck called the Karnival Assassins from Big Blind Media and the U.S. Playing Card Company. 
The cards feature skeletons and like the original Karnival cards, were designed by artist Sam Hayles. In addition to a high grade stock the deck offers features for magicians that include: a subtle one-way back design and card revelations on the box's barcode and on a joker.
In the end, it's all about personal preference and the kinds of card that you like to work with and the design that best supports your performing persona. There are lots of choices out there and you can be free to perform with the decks that you like best.
More Reading:
Karnival Cards
Black Tiger Deck, Gaff Deck & Black Book
Xtreme Beginnerz
Comments
My main concern is with actual gaffed cards; no matter how many gaffed decks Ellusionist make, it never competes with the breadth out there on the market for “normal” Bikes. So if I have got True Astonishments for instance, I have a little yellow envelope full of gaffed cards for red or blue Bikes, and there is no way in hell they will all be released under Karnival, Ghost or Arcane flavours, as delicious as these flavours happen to be.
I think that the themed cards invite closer scrutiny and greater inspection. You hand them out and people do look at them more closely. Once a spectator has assured themself that these wonky looking cards are on the up-and-up, their level interest is piqued. At least, this has been my experience.
Great comment and I appreciate the open mindedness to cards. It is a choice. Thanks for expressing this view!