marekgebka uses Foundation
I use it for a lot of professional work where I might need more than just a responsive grid. Has a great set of mixins and components and also some nice JS-modules. I love that its so style-agnostic. Really easy to add custom styling.
kfancy uses Foundation
Foundation has been my choice for years over Bootstrap and other similar CSS frameworks due to the naming conventions, well-designed built-in components, and it plays well with React when I'm not using ElementalUI instead.
AlexanderSix uses Foundation
My front-end framework of choice. Foundation is super-simple to use for just about anything, and directs my focus always on mobile-first.