The biggest difference between a bank and a credit union is that a bank is a for-profit institution, while a credit union is a not-for-profit institution. Both function in similar ways and offer similar types of financial products. Credit unions are usually membership-based and more regional and have a less national presence. They do, however, often get high customer satisfaction over traditional banks. So if you have sufficient branches near you, credit unions can be a great choice for a number of kinds of small businesses.