comparison among these frameworks

Vermillion design came with an overall comparison against popular (Bootstrap, Foundation, Skeleton) Responsive CSS Frameworks.
They have compared the frameworks based on following sections:

1. Overview: This section basically compares Version, Creator, github and license among Bootstrap, Foundation, and Skeleton.
2. CSS: This section compares CSS preprocessors used by them.
3. Grids and Responsiveness: This section compares the syntax and semantics of grids used by these frameworks.
4. UI and Widgets: This section compares the different types of widgets supported by these frameworks

You can find detail comparison among these frameworks here:
http://responsive.vermilion.com/compare.php