I posted a little while ago about blog searching options. As others do, I have several 'ego feeds' set up to track posts. No service is miles ahead of the others, although Technorati and Google's Blogsearch are what I tend to watch. That said, others will occasionally have something that those do not.
However, something that I have noticed recently is that PubSub doesn't seem to pull in mentions from outside North America, or in non-English languages, as much as the others do.