Here’s a very interesting article posted yesterday by Steve Souders on his blog, which outlines a disadvantage of using @import over standard the link tag. See here:
http://www.stevesouders.com/blog/2009/04/09/dont-use-import/Â

The crux of the article is that @import results in stylesheets being downloaded sequentially rather than in parallel, resulting in slower load times. It covers a variety of cases; multiple @imports, @imports + link tags, and more.

The article is entirely about IE, saying that the problem exists on version 6, 7 and 8. The conclusion is that standard link tags work consistently over all browsers and should be used instead.