Google's Web Starter Kit vs Initializr

Since a lot of web designers these days don't use the plain old CSS, instead they use a CSS pre-processor (like Sass or Less). Thanks to Sass support web designers can easily add GWK to their workflows.

Starter Kit includes Autoprefixer that takes care of vendor prefixes.

Since the base skeleton provided by the Web Starter kit is authored by Google itself, it's pretty much understood that the template is optimized to the max, for performance. If you test a site (on Google PageSpeed Insights) built by the GWK you can be sure that it'll always achieve a very high score.

Since most of the websites that are currently being built (or any website that was built after 2012) are responsive, a 'scaffold-ed' website skeleton without any responsiveness would be pretty useless.

Helps to build website faster by refreshing the page automatically as you save the source file changes.

Gulp script includes tools for image optimization, JavaScript & CSS minification & optimization and HTML minification.

In case you want to try out your shiny new site on your mobile phone or another PC. Just type in the command gulp serve and load up the provided server address from another device to see how your website looks and performs.

If you use the Gulp build system and are familiar with its environment, you can directly use Web Starter Kit's Gulp build script to build your next GWK based project.

BrowserSync offers a browser live-update solution across multiple devices. And it works with basically every desktop and mobile browser. Even IE7.

There's a Yeoman generator for Google's Web Starter Kit available. To install (requires Node, Ruby, Gulp, and Sass):

sudo npm install -g yo generator-web-starter-kit
cd project-root-directory/
yo web-starter-kit
npm install
gulp serve

Initializr allows you to "fine-tune" your template by allowing you to take the good stuff from both HTML5BP and Twitter Bootstrap and download a mashed up basic template, which you can begin development on.

Initializr is very well documented, even though it itself being a pretty easy to understand and use tool. The documentations are available in different languages as well, available via the International Guides section on the website.

With initializr, very little setup is needed. All you need to do to be ready for development is provide your favorite template maker (HTML5BP or Bootstrap).

It's not really a template by itself but allows you to create a custom template from known good technologies.