Basically I am wondering what is the advantage / purpose of using @import to import stylesheets into an existing stylesheet versus just adding another ...
<link rel="stylesheet" type="text/css" href="" />
to the head of the document?
From a page speed standpoint, @import from a CSS file should almost never be used, as it can prevent stylesheets from being downloaded concurrently. For instance, if stylesheet A contains the text:
@import url("stylesheetB.css");
then the download of the second stylesheet may not start until the first stylesheet has been downloaded. If, on the other hand, both stylesheets are referenced in <link> elements in the main HTML page, both can be downloaded at the same time. If both stylesheets are always loaded together, it can also be helpful to simply combine them into a single file.
There are occasionally situations where @import is appropriate, but they are generally the exception, not the rule.