I hope they take your criticism constructively though, because I agree. I'm a longtime Bootstrap user but wouldn't be opposed to trying out Foundation...but I honestly don't know where to start.
Like Bootstrap, Foundation has a nice big "Getting Started" link to click on. OK:
http://foundation.zurb.com/develop/getting-started.html
Neither Foundation's or Bootstrap's "Getting Started" page is particularly interesting to me. But Bootstrap also has a "CSS" nav button that my eye naturally gravitates to, right next to "Getting Started". I click on that, and I see right away what opinions and conventions Bootstrap has, starting from the HTML5 doctype. The sidebar on the right makes it easy to get to specific topics of design, such as "Tables" and "Grid system".
Where is the corresponding overview page for Foundation? They also have a "CSS" link but it's not in the nav bar, it's nearly below the fold on Getting Started. And clicking that brings me to this Download page. Is that intentional? There's already a prominent "Download" link in the nav bar. I expect CSS to take me to some kind of page that demonstrates the CSS conventions. Clicking on "Sass" takes me to an anchor on the "Installation" page for the "command-line tool"...what does that have to do with how Sass is used?
I guess the next best link is Kitchen Sink, which takes me here: http://foundation.zurb.com/sites/docs/kitchen-sink.html
And I get an alphabetical list of elements, the first one being "Abide", which...I have no idea what the name has to do with the element, whatever the element does. The Kitchen Sink page has two sidebars, and I'm not sure which one I'm supposed to focus on.
Maybe I'm an edge-case user, in that I don't really care to read tutorials to figure out how to use a front-end CSS framework. But that's what was appealing to me about Bootstrap from the very beginning. The design looked nice, the writeup of Bootstrap's most prominent elements and conventions had me sold right away. I didn't even know what a CSS framework was before Bootstrap, and had up to that point been satisfied with hand-coding CSS for every site. So whoever designed and edited the initial landing page for Bootstrap was doing something right, to so quickly make me realize my ignorance :)
Edit: Like the parent commenter, I regret my dickish tone of criticism and realize I need to take a nap. Not knowing much else about Foundation other than high praise from devs I respect, I would love for it to be as ubiquitous as a solution. Just pointing out that whatever technical flaws Bootstrap has, its introduction and overview docs are highly accessible and appealing.