Reviewing MS Dictation
Jarred Walton at Anandtech has posted perhaps the most thorough comparative review of Microsoft's Office 2003 Speech Recognition vs. DNS 8 that I've seen. He dissected the entire experience, reminding me of those anally-detailed digital cameras reviews on dpreview.
If raw accuracy is what you care about, the bottom line is that the two systems are pretty similar. Here's his summary chart:

He analyzes a bunch of other things and shows how MS is noticably better at fast dictation speeds, and generally uses much less CPU power. DNS, on the other hand, is more polished, with a better overall editing experience.
I won't go into all the reasons why accuracy is hard to measure, but I think this shows that even the 5-year-old SR that you get in Office 2003 is pretty good. I can't wait for Jarred to try our much-improved system.
[via Rob and also discussed at TabletPCBuzz]