Peter Wilson

Many browsers will not render your webpage until the print.css is loaded. Delay Print CSS prevents this from happening. Once your page has fully rendered (including JavaScript, images, etc) your print stylesheets will be loaded.
Using the methods described in a <a href="http://bigredtin.com/behind-the-websites/delay-loading-of-print-css/" rel="nofollow ugc">recent blog post</a> this plugin uses JavaScript, with a non JavaScript fallback, to load your stylesheets last.
If your WordPress site uses jQuery then it is used to load the stylesheets, otherwise the plugin outputs its own JavaScript.

Delay Print CSS

Prevent your print stylesheets from delaying rendering of your website

jshoptaw

This plugin allows you to use uploaded CSS files that can be used across themes without having to edit any theme files or use FTP.
For example, if you wanted to use Font Awesome on your site but your current theme doesn’t include it (or you know you want to use Font Awesome regardless of what theme you’re using), you can simply upload the <code>font-awesome.css</code> (or <code>font-awesome.min.css</code>) file using the WordPress Media Uploader then activate said stylesheet in the Theme-Independent Stylesheets (TISS) settings. That CSS file will then automatically be included on your site no matter what theme you’re using. Even if you switch themes, the CSS file will still be called in your site’s <code><head></code> (as long as the theme is coded to properly use <code>wp_head()</code>, which most themes are).

Theme-Independent Stylesheets

Allows for use of uploaded stylesheets (.css files) to be used alongside any theme

Delay Print CSS vs Theme-Independent Stylesheets