Wow, that was fast !
I love Foundation, but I had to switch to Boostrap because I found it... ugly. And Bootstrap is great to quickly create "pretty" prototypes. But I've always found Foundation having better... foundations. I've used both on numerous projects and here's my take :
* The grid system now looks like bootstrap, and I don't like that. You have to choose the type of column you want to use (and I don't want to be bothered by that). so no .six anymore, it's .medium-6 or .large-6 or .small-6... They should call the .small-6 just .six so we know its the default one.
* It does look a bit better, although they removed styling of the radiobox in forms? Why?
* Overall I still prefer bootstrap's theme, I wish Foundation would offer an optional theme like bootstrap 3 does.
* OffCanvas menu is great ! I can already see plenty of applications (but for mobile only)
* The CLI is a nice thing to have but I'm gonna stay away from it. I like the easiness of copypasting files to quickly begin a small project.
* Documentation is hard to go through, doesn't allow to glance at what it offers. It's a huge improvement from F4 or F3 though.
* I use sublime text snippets all the time and this might be a huge addition!
* I like the JS that verifies forms. I usually always use this on my projects so it's nice to have it by default.
Overall I don't really know if I should switch back to Foundation. But I'll definitely use it for my next project to see how good it is.