I personally love Zurb. The biggest reason being better names for things such as classes and less influence on the overall design.
Unfortunately I still stick to Bootstrap because the entire industry uses it, thus having more support.
Awesome job on the ZURB Foundation 6 launch. Great graphics, sci-fi theme, some awesome new features for the framework. The flexbox grid, yeti launch and the new menu component are worth looking at.
Can someone compare Twitter Bootstrap and Zurb Foundation in simple form (main advantages or hurt)?