Bootstrap’s big win for me is in responsive layouts. Responsive, meaning that you can visit the site with a small mobile screen or with a large PC screen, and the site will have a similar appearance. There is one package of source code supporting all device sizes. Boostrap provides a grid layout system, which simplifies the code. It is more straightforward than the underlying relative and absolute positioning, and obsoletes the old methods of layout by table or (egad) frames.
The responsive layout on my site is not perfect. On a desktop, I would prefer to have the navigation controls in the left column, but on a mobile I prefer them at the top of the main column as above. There is probably an easy way to do that, check back soon.
But what about SEO. Will Google be unhappy that the content is conditionally visible? Google had problems with sites which had deceptive SEO in the form of hidden or small-font text. This page is not deceptive in that way, but it could trigger the alarms at Google. This issue is TBD.
What is content is loaded dynamically using AJAX XHR from a WordPress server? In this case, the HTML file does not contain content, but instead has (view the source to verify!):
<div ng-bind-html="pages.content.rendered" ></div>
What about Google’s Webmaster Tools Data Highlighter? Unfortunately, it does not work for me at the moment.
What about older browsers? Then all pages will appear, and again that is a good fallback. Some browsers showing this problem are MSIE 6, Konqueror 4.8, and Lynx.