The UK is also a slightly dodgy example because the Cooperative Bank managed to implode in spectacular fashion mainly because the board didn't have many people

The UK is also a slightly dodgy example because the Cooperative Bank managed to implode in spectacular fashion mainly because the board didn't have many people with any idea about finance, and their Chief Executive, who had a politcial background, ended up being arrested after being caught by the papers trying to buy drugs. There are some really good examples of building societies over here, Nationwide seems to consistently do retail banking very well. But they are not a panacea.