Bootstrap vs Polymer: What are the differences?
Bootstrap: Simple and flexible HTML, CSS, and JS for popular UI components and interactions. Bootstrap is the most popular HTML, CSS, and JS framework for developing responsive, mobile first projects on the web; Polymer: A new library built on top of Web Components, designed to leverage the evolving web platform on modern browsers. Polymer is a new type of library for the web, designed to leverage the existing browser infrastructure to provide the encapsulation and extendability currently only available in JS libraries. Polymer is based on a set of future technologies, including Shadow DOM, Custom Elements and Model Driven Views. Currently these technologies are implemented as polyfills or shims, but as browsers adopt these features natively, the platform code that drives Polymer evacipates, leaving only the value-adds.
Bootstrap and Polymer can be categorized as "Front-End Frameworks" tools.
"Responsiveness" is the primary reason why developers consider Bootstrap over the competitors, whereas "Web components" was stated as the key factor in picking Polymer.
Bootstrap and Polymer are both open source tools. It seems that Bootstrap with 134K GitHub stars and 66K forks on GitHub has more adoption than Polymer with 21.1K GitHub stars and 2K GitHub forks.
According to the StackShare community, Bootstrap has a broader approval, being mentioned in 7046 company stacks & 1115 developers stacks; compared to Polymer, which is listed in 42 company stacks and 32 developer stacks.