Microsoft showered Gold subscribers with a ton of games over the last year. To be more specific, $1,029 worth of games were brought out for free to Gold subscribers over the year - a sort of massive value, assuming you're downloading every one of the games each month.
Polygon put together a comprehensive list of what came out this year through Games with Gold, breaking it all up month-by-month. The collective values of the games that came out each month averaged anywhere from $60-$100, and generally held fairly average Metacritic reviews.
While there aren't many months that were slam-dunks, the Games with Gold program fulfilled its purpose. It successfully managed to give gamers something new to play every month, so they can stay entertained between their big, blockbuster purchases. By design, games come out in various genres to fill in the gaps for all of the different tastes that are subscribed to Gold, so there's a little something in there for everyone.