I think he's just pointing out the fact that you get subtle variations at different sizes & with different CSS settings. I don't think he is saying not to use

I think he's just pointing out the fact that you get subtle variations at different sizes & with different CSS settings. I don't think he is saying not to use them. In most cases we just want the icons to look "good" and it doesn't matter if there's subtle differences in anti-aliasing. But other times a designer may want to be pixel-exact, in which case sprites still serve a purpose.