NEW YORK (MainStreet) — Nobody is lighting any birthday candles, but at four months and counting, it's worth taking stock of where Apple Pay, the technology giant's digital consumer payment system, stands today.

Phoenix Marketing International, out of Rhinebeck, N.Y., has done the legwork with research showing Apple Pay has an "impressive" adoption rate of 11% of all credit card-owning U.S. households and 66% of all iPhone 6 owners. Of those users who deployed Apple Pay onto an electronic device, 82% linked Apple Pay to a credit card, while 53% linked to a debit card. Twenty percent used Apple Pay with a prepaid credit card.

Altogether, it's in use in 8 million households, and by 12 million U.S. consumers, Phoenix reports.

On the retail end, Apple Pay isn't exactly setting the world on fire, despite high demand.

"The early-on transaction potential is being undercut by low repeat usage and lost payment opportunities," says Greg Weed, director of card research at Phoenix. "The demand is there: 59% of Apple Pay users have gone into a store and asked to make a purchase with Apple Pay. But so is the disappointment: 47% visited a store that was listed as an Apple Pay merchant only to find out that the specific store they visited did not accept (or were not ready to accept) Apple Pay."

Technical snafus are also holding back use, although that's not uncommon for such rollouts. "Even though Apple Pay users generally give the scheme high marks and 23% expect to significantly increase use over the next three months, problems at checkout are downgrading transaction potential," says Leon Majors, senior vice president at Phoenix. "Two out of three Apple Pay users have reported a problem at checkout — mostly related to terminals not working or taking too long to make the transaction, inaccurate posting of transactions and the inability of cashiers to help buyers who needed assistance in using Apple Pay." 

Early adopters agree the rollout has been rocky. "I've found retailers to be slower in adoption than in more metro market states," says John S. Oxford, director of communications at Renasant Bank, In Tupelo, Miss. "I know in at least three cases I was the first customer to use Apple Pay in three different franchise restaurants in Mississippi — Firehouse Subs and two Subways."

"The adoption of retailers is what I see as the biggest barrier right now, even though it's so easy to use and there is that cool factor as well," Oxford says. 

Some retailer woes are easily fixable.

"I was at Staples last weekend and it was the cashier's first time accepting Apple Pay," says Scott Bloom, founder of Bloom Real Estate Group in New York City. "She needed help processing my payment, but that's not surprising since not many retailers accept Apple Pay."

Retailers, especially smaller ones, say Apple Pay has long-term sustainability, but market entry hasn't been easy. "I love using Apple pay, and use it very often when available," says Keith Miller, co-owner of Pampered Pooch Playground in Minneapolis/St. Paul, Minn. "We own three small businesses and would love to have them accept Apple Pay, but honestly there is no real solution for small business yet. Our point-of-sale system does have a solution, but it is bulky and not ready for prime time yet."

"That said, I wish we could take it," Miller says. 

— Written by Brian O'Connell for MainStreet