I can only speak for myself here so please take that into consideration when reading this. JMO.
Foo Fighters is a really great game. It's fun, has fantastic flow and a unique layout. The sounds and callouts are great and the overall art package is strong.
The code is fairly linear and feels similar to Deadpool (which makes sense because it's Tanio on both): mode, maybe stack a multiball, get to a mini-wizard mode.
Godzilla is different. It's also fun and has a fairly unique layout. The art package and sounds/callouts are also excellent. What is different (to me) is the strategy of moving around cities, the optional city objectives, the stacking, the annihilation/carnage bonus potential... There is no standard way to play the game and score points. I've recently learned that Terror of Mechagodzilla is so much more lucrative that I'm beelining it in competition play over Monster Zero.
At any rate it is all subjective. I enjoy the complexity and depth of GZ more. It reminds me of a Lyman-coded game where scoring balance takes precedence so it doesn't become a do-this-then-this-then-this-then-this-then-this game. Foo does not...yet. I certainly hope it does because better pinball means more players, and more players means more fun to me.