Well if Google buys Feedburner then it will probably start a feeding frenzy of buyouts and sprout ups in the feed arena - just like their purchase of Youtube and DoubleClick created a surge in those markets. So then who will buy Technorati?
I don't know the numbers, but I use both. I almost think Technorati would be a smarter move for Google. If Alexa eyeballs mean anything.
Here's the traffic stats.
Feedburner.com/ vs Technorati.con