A credit union is like a co-op. You are a member, not a customer. Credit unions are limited in membership to only certain groups (although in reality, many have easy ways to become members of said groups).

Most credit unions are small, although the largest credit union, Navy Federal, would be the 36th largest bank in the US were it a bank, clocking in about the same as Discover Bank.

Credit unions tend to have better rates for their members than the average bank, however while many are also pretty strict in their underwriting, they also have a reputation of considering the whole individual rather than strictly the numbers.

Most credit unions belong to an ATM network and often have shared branch reciprocity, so you just need to know which network and what branches of the local CU work for your own. So, say you were in NH, and you wanted to do something, but your CU in Florida is a co-op sharing member, you just look up the location on the website and discover you have 11 branches and 50-some ATMs available.

However, often small credit unions have small and weird web sites and sometimes no mobile app. They may not have all the services you want.

In general, CUs will not nickel and dime you to death with fees. They HAVE fees, however, not a fee for every piddling thing.