Here's my thoughts on the search tools that we looked at:
Bloglines Search Tool: I liked that you could narrow this down to your feeds only. I can see myself using that when I'm looking for a blog post I've read before, as opposed to just scrolling down until I find it.
Syndic8.com: Probably my least favorite of the four. Showed a lot of irrelevant blogs when I searched.
Topix.net: I liked how this came up directly with Tulsa news and blogs on it, and also how you could search other locations (I did Charleston, WV, where my husband's family is from). Keyword search was okay, not great.
Technorati: The one I liked the best. The page is a little cluttered, but I feel like I got the best results on my seaches here.
I have to admit I didn't add any blogs to my Bloglines, because I have plenty.