So, this card has received a lot of hate in my local meta. Words like 'it is just objectively bad', 'strictly worse than putting in better cards', and 'the math doesn't work out' have been rather liberally bandied about. Which made me think a fair amount about evidence against such statements. I'm happy to see that most of what I wanted to say has already been said. Great job Netrunner community! Nonetheless, I'm going to try and convince you that not only is this card not objectively bad, but it's actually fantastic in the right build.

The criticism I want to attack most directly is that the math doesn't work out. In my mind, when discussing economy most Netrunner math starts with a fundamental ratio

1 card: 1 :1

Building economy for your deck is all about how you warp this ratio in your favour. Magnum Opus doubles your click efficiency giving you 2 per while Professional Contacts does so by giving you a card and a for each click. But of course, they don't offer you this efficiency for free. You need to invest and in that case of Magnum Opus, as well. These are great examples because it's fairly obvious how their efficiency works. Okay? Cool.

But we're not talking Shaper here, we're talking Criminal And to be clear, this really is a Criminal card. As tiediedvortex points out, you want to run all 6 and I can't imagine any deck sparing 6 influence for it. Also, this is a draw engine with economy attached and not the other way around. So let's compare it to some event based draw in criminal. It's a pretty short list. Fisk Investment Seminar. And done. Oh, did we mention it was priority and gives your opponent that same amount of cards? Economically it nets you only 2 cards (over what you were already getting anyway) and it still sees play. So Exclusive Party is either the best or second best event draw Criminals have. Sure, there's also Drug Dealer but again it comes with the drawback of negative drip economy you can't turn off and it's a resource.

What about in faction event based economy cards? What if we put those in and and just to draw? I think the most fair comparison would be to ditch your 6 Exclusive Party and add 3 Sure Gamble and 3 Easy Mark. If I play all of those, I net 21 (3 for each Easy Mark and 4 for each Sure Gamble)...but I'm also down 6 cards. So really by our fundamental ratio I net 21-6 = 15 if I want to replace those cards. That's an average of 2.5 per click I spent playing those cards. Which, what do you know, is exactly what you're making on Exclusive Party if you play them all. Of course, when you get that money is very different. We can't know what order you'll draw your EM and SG so let's assume that you are making the 2.5 average each time. The tipping point then is at card 4. At that point you've made 10 on average. Exclusive Party has made 6 and 4 cards, net 10. And let's not forget the potential tempo hit that comes with Sure Gamble - you have to click up to 5 if you want to use it sometimes. Exclusive Party is never a tempo hit, you can always play it immediately for effect if you like. So I will disagree with tiediedvortex here. You should expect to see at least 4 every game to be as good as the alternative event economy, although there is no doubt you want 5 and 6 (again presuming you don't trash any without playing them, I'll happily discard one of these on an opening Andromeda: Dispossessed Ristie hand)

So, the math works out when you build a deck where draw is more important than burst economy. The most obvious case is combo decks, like stealth that sees lots of play in criminal or Snitch & Au Revoir. You need to get your pieces out fast. Let's not forget you can go tag-me with this economy without fear.

So far we've just talked Criminal card pool. Street Peddler would work well with it or Faust as Yziel mentioned. It could even possibly work with Faust and Drug Dealer combos which giving you burst money when you need it. I think this is a subtle and well-designed card. It's not as obviously 'good' for all decks as something like Sure Gamble but it plays an interesting role for Criminal builds. Sorry I'm so long-winded.

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For total transparency: There's also Express Delivery -- costs one 1 draw 1 card, but is -slightly- more likely to get you the card you want. And Lawyer Up, which is really more about getting rid of tags... but if you need to get rid of two tags for cheap, gets you 3 cards for free while you do it. It's still a solid choice for 1st or 2nd place for event card draw out of Crim. —
Good catch @Goldstep thanks, I'll edit that in —
"At that point you've made 10 credits and are down 4 cards, net 6. " But isn't the 2.5 average already taking into account the card difference? Seems to me that you are counting it twice. —
Not exactly. Think of it another way, by card 4 with EP you always have 4 new cards and 6 credits, net value 10. By card 4 playing Sure Gamble and Easy Mark you have, either 13 (4+3+3+3), 14 (4+4+3+3), or 15 (4+4+4+3) credits, therefore an average of 14 credits but you are down 4 cards so net value 10 as well. Which is better depends on how you've tweaked your draw and econ engines. —
Thanks for pointing that out @bbbbbbbbba, my math was in fact wrong! They do meet at 4 cards, but value is 10 for each at that point. —
No, this is still wrong. Suppose you start with 0 credits and 4 cards in hand -- you can have 4x Exclusive Party, or 2x Easy Mark and 2x Sure Gamble. If you play out the 4 parties, you end up holding 4 cards and 6 credits. If you play the marks and gambles you end up holding 0 cards and 14 credits. If you consider 1 credit as good as one card, then the mark/gamble player is up by +4. If you consider 1 card to be worth 2 credits, it's a break-even. —
You are correct @orionJA. Math is the worst it turns out. —
Can't seem to edit the original post though. Sad days. —