Thank you for the welcomes, I'm glad to be here.
Don, thank you for all the advice and your thoughts, very much appreciated. The "plan" I have in my head is, 'wait until you're good enough to avoid destroying the decks before you open and play with decks worth more than $5'. Which, is a good plan theoretically, but that day when I'm "good enough" will keep getting pushed further away. I mean, I destroyed a few standards before I was good enough with the Faro to NOT obliterate the edges of a deck, so in that sense it was smart. But on the other hand, now I'm waiting until I'm good enough with the Lepaul spread not to leave an asymmetric bend in the cards (if that's even possible). Sooo it's an ongoing quest.
For the time being, yes I'm one of those people who spends my cash on pleasing looking decks and complete sets. I even buy decks I know I never want to open, like the current Titans Kickstarter deck for example. I very much dislike the faces of the cards, but I love the backs and I love the tuck boxes. So I burned $52 on that set of all three.
As for your comment on performances using common vs custom decks, I never planned to perform anything in front of others so I never thought about that. But what you're saying makes absolute sense, seeing something common puts people at ease oddly. I guess I hope that one day custom decks will start becoming common enough in magic performances that people stop relating it to trickery by association. That way we get to see some deck diversity.
On that note, what percentage of custom decks right now do you think are marked? I never open decks enough to find out, but I do know there are a number of them which are definitely marked. Like, I'm pretty sure all (most?) of the Madison decks are marked. So I'm sure other decks do it too, but I don't really have a good idea of how many.
Re performance with custom decks, it's not about people thinking they're trick decks. They usually don't. It's a bit of a myth among some that custom equals trick deck in the minds of spectators. Actually, the bigger issue is that when you perform with a trick deck, even if it isn't some special limited edition, the more interesting and unique the deck's appearance is, the more your spectator will be focusing on the cards and not on the trick! For some, that might work as a form of misdirection, if your object is to do something elsewhere while there's all googly-eyed looking at the cards, but for most, when the spectator isn't paying attention to the trick much at all, there's less of an impact when you finally pull off "the prestige" at the end.
Cardists have noticed this as well and many will actually opt for a fairly simple design over an attractive custom design - but that's more of a preference thing for cardists, since there's no trick being performed and the cards are indeed integral to what the cardist is doing. Some look for a middle ground of sorts - a deck with fairly standard faces but with backs intentionally designed to make for more attractive flourishes, such as the Virtuoso deck series produced by the cardist team of the Virts.
As far as decks being marked, particularly custom decks, the number is much smaller than you think. Not all Madison decks are marked, though it's true that many are - his deck series probably has more marked decks than almost every other. Only a very small number, perhaps a few percent, are actually marked. It can actually hurt sales to sell a marked deck to the general public. Poker players, not wanting to be accused of cheating, won't even touch a one-way back design, never mind a deck that's known to be marked.
Plus, there are a variety of ways a deck can be marked. There are factory-printed markings and "homemade" markings. There are markings visible to the naked eye and markings that require a special method to become visible, such as using a filter-equipped pair of sunglasses or defocusing your eyes. There are markings that are well-suited for card games (usually when the marking system is confined to the upper-left corner and its inverse, because that's the corner visible in a card player's hand when the cards are held fanned) and markings that are poorly-suited for card games (the NOC decks from version 2 forward have either full markings or suit-only markings, depending on the exact model, but the markings require that you be able to see the entire card back to be read). There are markings that require memorizing some kind of system or code to be read and there are markings that are written in plainly-readable ways (usually letters, numbers and possibly suit symbols) if you know exactly where to look in the card's back design. (Decks using plainly-readable markings are sometimes called "readers" for this reason. Readers have to be well-designed to keep their marks hidden - if not, even a casual examination of a single card's back will reveal the markings.)
The different systems fit different purposes - a system ideal for a card player might not be as good for a magician, since people familiar with card marking might look in the ideal places that card cheats would use to mark cards for readability in one's hand.
There's even a marked deck out there that has zero markings of any kind externally - the cards are factory printed with RFID chips in them, making them readable using a tiny chip reader you can wear on your wrist or conceal in a tuck box. It can tell you what a specific card is by two methods - either by vibrating against your wrist in a pattern to tell you value and suit, or by using a Bluetooth-connected smartphone equipped with their reader app, but you have to be within Bluetooth range of the reader - typically not more than about three or four yards, depending on the local environment. You don't even need to see the card itself to know the value and suit, as long as it's within range of the reader (within inches) and the rest of the deck is far enough to not be in range - it could be in a pocket, in a sealed envelope or under a napkin or tablecloth. It's safe to say this deck is not common at all - it's VERY expensive, running in the low three figures for the cards and all the necessary hardware and software.
If you have your hands on a deck, one of the more effective ways to spot the more detectable, visible marking systems (the types commonly used by magicians and less-sophisticated, low-tech card cheats) is to employ the riffle test, sometimes called "going to the movies." As a kid, I'm sure you've played with or saw flip book animations - a series of drawings are sketched onto the corners of a pad's pages, each one slightly changed from the last, so when flipped, you can see the drawings "come to life" as a primitive but effective form of animation. The riffle test employs the same principle. Hold one end of a deck firmly while riffling the cards at the other end, just like a flip book. In a standard deck, all the backs are identical and nothing should change, making for a very boring animation. In a marked deck using visible markings, all the backs are different in some small way, and if you look carefully, you'll spot the changes while riffling the cards, though it might take you a few tries if the marks are particularly subtle.
I've managed to reverse-engineer the marking systems of a few decks using a modified riffle test I'd thought of - I sorted the cards into suit order first, just to see what changed at the quarter, half and three-quarter points of the deck as I riffled, then sorted them in value order with all the aces together, then the deuces together, etc., all the way to kings, then riffled to spot the subtle changes in the marks as I flipped from value to value through the cards. If the cards are randomly mixed, all you see is little flickers happening in a random order, just as random as the order of the cards, but if you sort the cards as I described, you can more easily see the changes from suit to suit and value to value, charting the differences more easily - it's like watching a slow-motion animation where the frames remain the same for thirteen frames in a row (when looking for suit changes) or four frames in a row (when looking for value changes).
One interesting caveat, when looking for marked decks. Due to issues regarding copyright and trademark law, the US Playing Card Company (USPC) doesn't allow modification to certain elements of their classic deck designs, most notably, the backs of their still-in-print decks which use artwork too old to be protected under copyright law. They have to be protected as trademarks, and in doing so, the company can't allow "dilution" of the trademark by permitting variants of the trademark to exist in the marketplace. For making marked decks or gaff cards, these would require alterations of the classic back design, which means that the company will no longer print them in designs such as the Bicycle Rider Back, the Bee Diamond Back, etc. There are two modern Bicycle backs, both young enough to be protected by copyright - the Mandolin Back and the Maiden Back. These were designed and tested to be similar enough to the Rider Back that most spectators won't tell the difference, but they're unique enough that they don't represent infringements or dilutions of the trademarked backs. Gaff cards and marked decks are available in these designs and USPC will print versions of these designs that are modified, at least until those copyrights run out, but that won't be for perhaps a hundred years or more. This also means that older, factory-marked versions of the classic designs are highly sought after and go for a significant premium over other marked decks.