What are the major differences to having your mortgage, credit, savings/chequing accounts with a credit union (or caisse populaire, in Québec) versus just a regular bank?
Both provide deposit insurance. Credit unions provide it through the National Credit Union Association (NCUA) versus FDIC for banks. NCUA is an "independent" federal charter whereas FDIC is straight government.
Hope that helps.
In Canada your deposits at a credit union are 100% insured, as opposed to banks insured through CDIC where it is limited to $100,000 per person.
Credit Unions are cooperatives, and you are therefore a part owner of the institution. They generally treat their members better and are more lenient with them than with commercial banks. They are also more focused on community benefit and customer welfare than corporate profits and shareholders.