I have to agree with Robert Scoble that Google's blog search not as good at link searching.
The only feature I use the various blog search engines like Feedster, Technorati, IceRocket and Google Blog Search for is looking for references to my posts which may not have shown up in my referer logs. Therefore, the only feature I care about is link searching and my main quality criteria is how fresh the index is. Here, Bloglines Citations Search is head and shoulders above everything else out there today. I've been using the various blog search engines every day for the past few weeks and Bloglines is definitely at the head of the pack.
Compare and contrast,
http://www.bloglines.com/citations?url=http://www.25hoursaday.com/weblog
http://blogs.icerocket.com/search?q=http://www.25hoursaday.com/weblog
http://blogsearch.google.com/blogsearch?hl=en&q=link:www.25hoursaday.com/weblog
http://www.technorati.com/search/www.25hoursaday.com/weblog