Unfortunately, I was travelling and couldn't weigh in at the time of the debate. Stale as it may be, here's my two cents:
If you are in the top thousand in Technorati, they will do what it takes to keep you happy if you complain loud enough. Otherwise, you're fukt.
Speaking of my own experience: when I switched, October 1, 2006, I went from a Google Page Rank of 6 to 0. I am still at 0. Nonetheless, I seem to google high for terms which occur on my blog: at one point the Guardian cited me as "Best of the Web" when all I'd done is blog about a story they'd carried in their normal paper!
The sum total of what I know is that WordPress blogs have a LOT of google juice, and don't do too shabby on Technorati either. The numbers? It took me from Feb. 24 to Oct 1 to get to 21,000 on Technorati, but it only took me from Oct 1/06 to January 16/07 to get to 22000 in Technorati. If you have a following who is already linking to you, you'll gain ground far faster than another blog who is starting from scratch.