I’m currently reading up on Foundation and the key differences between foundation and bootstrap. My first serious project is working with 5.5.3.
Because I mostly use plain html / css there is zero difference between the frameworks in terms of how I design - more Foundation is less bloated (out the box) - similar to bootstrap I can create my own custom version http://foundation.zurb.com/sites/download.html/
I only need the essentials, as my main reason for using a framework is to speed up my design process and the responsive aspect.