Lee, I'd like to personally welcome you to our humble forum! We love getting designers in to comment, especially ones of your caliber.
I think the artwork is great. It's reminiscent of the Infinity deck, but only in that it borrows some of the better elements in terms of the feel of the design - at least that's how it seems in my head. (Careful, peoiple have been known to get lost there from time to time...
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MrMollusk makes an interesting point regarding the banners that you have at the edges of the backs and faces. While I see no problem with the side banners, they'll look great ONLY if USPC doesn't screw up the registration between the fronts and the backs - which they practically always do to some degree or another, which in your case depending on the severity of the error would render the banners visibly misaligned from front to back.
You run into a similar issues with the banners for the court card indices, with the additional complication that if you do that style of banner only for the indices of the courts, you'll give away the location of the courts just by looking at the top or bottom edge of the deck. On top of that, a flipped court card would really stand out (some magicians do tricks involving inverted cards in the middle of the pack, as I'm sure you're already aware).
I think the side banners will work, despite USPC's tendency to have trouble matching fronts and backs. I'd recommend, though, making them the same color for the faces and the backs (that inverted card issue applies to that as well). If you want to have banners on the indices, I'd suggest making them fade to white as you approach the card's edge rather than printing them into the bleed.
In fact, if you wanted to minimize any changes for improved function, all the elements I mentioned could remain pretty much as you created them if you fade the banners to white and you'd eliminate all the potential drawbacks. Fans would look a little different than they would now, but that might be for the better - you'd have to test them out and see what you think.
That's my two cents, of course - you're the experienced designer here, right?
I simply am a stickler for functional design in a deck, regardless of the application (magic, gaming, flourishing, house of cards, etc.), and I really like the artwork on your cards a great deal.