The "con" would be falling earnings across most sites. I'm seeing that but, of course, I  can't be sure that DPC is responsible.

As Baldrick said, the con is cut throat earnings. Other sites will follow because it will become price wars across the board. DPC devalues your work, sends a message to the entire industry that contributors are okay with such low royalties, so why wouldn't other agencies follow? Fotolia has been deceitful for years, so I would also add that you don't yet know what's next when you are opted it, if they will even bother communicating unfavorable decisions (and they don't, for the record) in the hopes that contributors won't catch it. Just like DPC.  They automatically opted everyone in without their permission. Only when someone found out and Zhit hit the fan did they provide an opt out.  Once they provided an opt out they rushed in an extended license scheme to draw in more contributors. The bottom line for is is that once you opt in you are effectively telling the industry that this level of pricing is something for which you agree and others will follow.  If your work is on higher paying sites you risk losing that revenue stream (or lot of it) and receiving, in totality, less due to DPC.  It is a poison to micro stock and every contributor should consider the consequences of opting in.

Edit....I wanted to add that Fotolia is a vindictive agency. If you speak negatively about them and their policies and practices they will retaliate by closing your account. This happened to several people here on msg who exposed them, criticized them and encouraged others not to upload to DPC. That is a very poor character for an agency to possess and not one in which makes a contributor feel welcome, rather controlled not in just what you upload but what you say.

PRO: you can make Oleg and KKR even more richer (if that is what you desire)
CON: everything else!

Pro: It's another way to earn.

Con: It's another way to earn at the expense and risk of future earnings elsewhere. Every buyer who moves their purchasing over to DPC means a loss of that business elsewhere, and since pretty much everywhere else pays better, it's a loss of earnings for all of us. It is potentially a huge long-term loss for everyone, whether you're opted in or not. All DPC needs to achieve is even modest success to start to severely negatively impacting the entire market.

For me it was all cons.  The only reason not to opt out immediately was that it also meant opting out of Fotolia.  Once they offered an opt out specifically for DPC, that argument evaporated.

As for the cons, it helps to consider why subscription sales are good for suppliers.  In essence, a customer is buying more than he or she needs.  Once they've downloaded what they require, either they use some or all of their remaining downloads or they lose them.  So customers download a lot more than they need, and suppliers get more sales as a result.  Yes, each sale is for a small amount.  But if we get enough of them, they add up nicely.

I can see this "might as well DL; I've paid for it" attitude in my own sales.  I upload many images from my people shoots, and I often see five, ten, or a lot more downloads at the same time.  I assume those are from individual customers who use their extra DL slots because they like my subjects.  They don't need them, but they can download them for free.  So they do.

Customers have two purchase models: subscriptions where they pay very little per download but need to download a lot to get the value; and individual purchases for a lot more per purchase.  (Credit packages are individual purchases with a volume discount; the customer gets a price break but still pays a lot more per image than a subscription offers.)  As suppliers, we get a combination of lots of small sales (subscription) and fewer large sales (one off/on demand/credit sales).

What DPC offers is per-image pricing that's close to subscriptions but without the benefit of lots of sales.  It's the worst of both worlds for suppliers.  And that's before we consider Fotolia's history of reducing supplier royalties.  Whatever pittance they pay us now will likely be reduced the next time their accountants decide they need more profit.  And if they succeed in closing down sales at other agencies with their low low prices and minimal commitment, why wouldn't they reduce royalties to the bone?  Fear for alienating their suppliers?  Not likely.

...Shutterstock which also has a subscription plans that you make from $0.25 to $0.38 per image. I would say it is the same as a Dollar Photo Club income with other name: 25-A-Day subscription plan and DPC pays you $0.25 to $0.40.

So, in sum, isn't it the same? I am wrong?

Yes, you are wrong.

You can't get a Shutterstock subscription for $10.

So, in sum, isn't it the same? I am wrong?

No, it's not remotely the same.  SS gives a subscription customer 25 download slots each day; whatever they don't use, they lose, which encourages them to download lots of extra images.  That means lots of extra sales for us.

DPC on the other hand sells image packs that they call a subscription.  The packs are small and cheap.  Unlike a subscription, the rights to download don't expire.  So use one or two, and the rest are waiting for whenever they're needed.  That means a customer can download just one or two images (much cheaper than an equivalent image pack at Shutterstock) and save the others for another time.  Nothing to encourage extra downloads; no "use it or lose it".  So the customer gets low prices per download and no incentive to download more.