If you've never experienced banking with a credit union, it can be a little bewildering. They use different words for everything, and your relationship as a customer is very different from that you may be used to with a bank. But credit unions are a very attractive alternative, once you get the basics.
A bank is run by a board of directors who answer to its investors, and whose only job is to create profit for those investors. Every fee, every product and service, and every procedure is about putting money into those investors' pockets. A bank is a business, like any other.
With a credit union, those investors are the members themselves. Opening an account at a credit union means becoming a part owner of the credit union. It's called a "share account," and it works like a savings account and represents your voice in the company.
Credit unions are usually smaller, regional and community-oriented, so by joining, you're also taking part in your local economy. And since they're not-for-profit institutions, credit unions share any year-end profits with their members through dividends.
On the other hand, they don't always offer a bank's conveniences. Some don't have very extensive ATM networks, so you could find yourself paying a lot of extra fees. They don't always invest in the newest online banking systems because of the focus on savings and profit-sharing goals, so if that's a premium service for you, make sure to investigate the online situation fully before choosing a credit union.