But the other factor is that, taken collectively, "credit unions are adopting mobile banking faster than banks," said Eads. "We see $1 billion credit unions offering the same depth of mobile banking services as $10 billion banks, and we see very small credit unions that have adopted mobile banking far faster than similarly sized community banks. It comes down to the commitment credit unions have to service. They know their members want mobile banking and they are responding."

"We are seeing even very small credit unions becoming early adopters of mobile banking," agreed Tim Wooldridge, a vice president at financial tech provider Fiserv. "They see the handwriting on the wall."

Exactly how popular is mobile banking proving to be with credit union members? "Typically, a credit union will see 5% to 10% of its members using mobile banking in the first year," said Sievers.

But every credit union experiences its own triumphs and disappointments as it rolls out mobile banking. Washington State-based Verity and Michigan First in Lathrup Village, Mich., are two credit unions that recently deployed mobile. Generations Federal Credit Union in San Antonio, meantime, just now is about to start implementation. But 1st Advantage Federal Credit Union in Newport News, Va., is currently  holding back.

Verity Credit Union, with $360 million in assets and 26,000 members, recently enjoyed a successful mobile banking launch. The tools went live May 2 and by the end of June, Verity already had 1,598 mobile banking customers, said chief marketing officer Shari Storm. "We are happy. There were no major glitches. This rollout met every measure of success."

One irony is that Verity did not back the mobile banking rollout with a big budget marketing campaign. Verity initially launched mobile banking with just a tiny notice on its website.

"About 50 members found it on their own and signed up," said Storm.

Once promotion kicked in, it remained fairly low key. But members have kept signing up. Storm pointed to two causes. "More people have smartphones, and we are in Seattle," a tech-focused city  and home to Microsoft. Members had been clamoring for mobile banking, and so when it was finally offered, they pounced on it, said Storm.

A fear had been that there would be many calls from members experiencing troubles with mobile banking– and few credit unions are set up to troubleshoot technology hiccups–but, said Verity tech specialist Jon Wu, "We've only gotten a couple trouble tickets. This hasn't been an issue."

Michigan First Credit Union, with 80,000 members and assets of $575 million, launched its mobile banking on Nov. 1, 2010, and at the end of July, 2011, it had 6% of its members using the tools, said Linda Douglas, vice president of marketing."We have seen very high penetration among our young members. But we have seen more penetration among other age groups than we expected."

"It would be great if we could double that percentage in the next year," she said.

Michigan First has been aggressive about marketing mobile banking to its members. "A month before launch we put up a countdown clock on a website. When we went live, we sent out texts to members who had signed up for cell phone alerts. We also posted YouTube videos. We want to get out the word to members."

"For us this has been a very smooth, very easy implementation. We wanted to make our mobile banking look much like our online banking, and we think that has made member acceptance higher."

Generations FCU, with 47,000 members and $400 million in assets, recently signed on to offer  mobile banking, said Chief Information Officer Wes Barnett. He expects to be up and running "within four to six months."

As for picking a mobile banking solutions provider, Barnett said, "We have had our eye on this market for some time. We looked closely at four vendors and made our choice." One selling point for Barnett is that the vendor he selected has provable and extensive experience working with the same core system Generations uses. "That should make implementation go more smoothly."

A couple other must-haves for Barnett: he wanted to use the same user ID, password and challenge questions as users had already signed up for with Generations' online banking product and he absolutely insisted on real-time integration of the mobile app with the core, so users can always access all accounts. "Not every solution we looked at could do these things," he reported.

1st Advantage FCU, with $500 million in assets and 60,000 members, knows its members want mobile banking. "We have definitely been hearing that from our members," said Jim Craig, vice president, marketing. But two realities, the din is of recent origin and the comparatively new mobile banking marketplace leave 1st Advantage hesitant to take the plunge. "We don't want to jump in with both feet because things are changing too fast," said Craig. But he also admits that "mobile banking has been front burnered because members want it."

He doubts mobile will bring in new members, but "we believe mobile will be an important member retention tool. That is why we need it."

"We want to buy time," he said, and that means he is searching for a low-cost interim solution that will give the vocal members who are demanding mobile banking much of what they are clamoring for but without making an expensive or long-term commitment. "We are doing our research now."

At many credit unions, cost is not the primary obstacle to mobile implementation. It's fears about mobile security, said Doug Varble, a senior vice president at payments technology provider Compass Plus. "Fear of fraud has impeded implementation," he said. But he also said: "I have not heard of significant cases of mobile banking fraud."

Nonetheless, both credit union executives and some members apparently are hanging back, in fear of hackers and other cyber bad guys. The antidote, suggested Varble, will be more and better fraud detection technologies specifically targeted at mobile banking. As that comes, the adoption will get faster still.

"Security always comes up," said Amy Wilkinson, Fiserv's product manager-mobile solutions, who points to another step in speeding adoption. "Consumers have fears, we know that. It's an opportunity to educate consumers, much as it was when online banking rolled out. There are a lot of unjustified fears. Education will help get past them."

Besides, said Verity's Storm, "I'm just not that concerned with mobile banking fraud. The worries seem exaggerated. At least we have had no problems."