Navy Federal Credit Union is a not-for-profit credit union with over 12 million member-owners. Time to close: Up to 30 days for purchase loans (up to 45 days for refinancing).Preapproval time: Can be instant (could take longer in some cases).Perks: 0% down payment loans, $1,000 rate match guarantee, up to $9,000 cash back through their RealtyPlus homebuying service in most states.Interest rates: Below national average.