Nice.

Super simple to install and add to any page or post.

However, adding it manually instead of a sitewide setting can be bit of a problem. It would be nice to see some basic settings of customizing it, such as no background or background transparency, change text color etc.

Can you please provide the CSS code to modify it?

See an example of what we did:
http://www.stressebook.com/blog/
This one was in the blog settings feature area, where you can add HTML, shortcodes or anything else to show up just below the header.

<div class="breadcrumb">
<pre><code>[yoast-breadcrumb]</code></pre>
</div>

We can also add it within each blog post at the top of the post in the editor. We used the HTML tab instead of the View tab in the editor.
Here is another example:
http://www.stressebook.com/good-stress-engineer-qualities-part-4/