Barclaycard's "Ring" Mastercard has been hailed by independent reviewers as one of the most unique cards available today, due to its radically different Value Proposition: Simple Value for Revolvers. 
Simplicity comes as an 8% rate, transparent fees, and few if any surprises. 
But beneath this simplicity lurks something much more robust. This is the world's first "crowdsourced card," letting users shape features and benefits through a robust community of cardholders and with direct participation of the Barclays Product Manager. 
Barclaycard Ring MasterCard ... is the most interesting credit card I’ve ever seen.
The Points Guy
Cardmembers are encouraged to join an online community built around the card, with conversations and threads on financial smarts, crowdsourcing features and frank discussions directly with the Barclaycard Product Manager, a true first in the category.
In other words, card holders can suggest and vote up/down features, designs, etc., and, perhaps more importantly, participate in the overall BUSINESS performance of the card - there's a transparent P&L posted in the community, and card members get a profit-/performance-sharing bonus each year direct from Barclaycard, the terms of which they can actually change.
This is all meant to give people a voice and engagement in how their card is operated and run, and a stake in the performance of the card. For example, members recently voted to change the terms of the performance sharing bonus, giving up some upside potential in return for smoothed-out bonuses. They also voted on the card design,  to offer a 0% intro rate for the first time this year - likely a savvy marketing move which may be responsible for a sharp uptick in acquisitions as of mid-2015.
And yet, it's still one of the best kept secrets in credit cards today. 
This card’s ultra simple Value Proposition + participatory community is SO differentiated for the category and not at all typical for what a card for revolvers tends to be, all of this radical innovation may be exactly WHY the card is still very niche in terms of membership. Furthermore, Barclaycard is far from a credit card powerhouse brand – so may lack the draw and awareness of AmEx or Chase, which doesn’t help.
But there's more behind the apparent lack of uptake of this proposition.
We know from our recent work in building a new value propositions in the category, that two dominant forces rule the credit card market today:
  1. Consumers have been highly trained by the category to go after low and zero APRs, and to try to transfer revolving debt from card to card as much as they can. While this take a lot of effort and has the potential to tear apart one’s FICO score, this “roulette” game seems to be one that consumers eagerly play, and the category makes all too easy to keep up.
  2. Consumers love the ‘game’ of scoring and managing credit card offers, of playing cards off each other, and taking advantage of great deals and offers to save money on fees and interest, and gain better and better rewards. A card that does not offer a steady stream of offers (e.g. more points, low/no interest, extra cash, etc.) actually gains fewer opportunities to capture more mind-share. (An analogy for this from retail would be what happened to JC Penny when they shifted strategy from deals and discounts to everyday low pricing. JCP’s market share tanked and the CEO lost his job – because the experience was somewhat boring and unrewarding for shoppers who have been trained to pursue the next big deal.)

So, net net is that an ultra-simple value proposition like this, which is meant to make consumers’ lives easier and richer, actually faces an uphill battle in trying to get attention and mind share in a highly crowded market that encourages other behaviors and seeds different attitudes. Consumers have been trained to believe they can ‘game’ the card APR system, by using multiple 0-APR offers, can get an even better rate than Barclaycard Ring’s 8% - even though the reality is likely that this card would be a far smarter financial move for most revolvers over the long term.