I've not used the Vista speech recognition program as this computer runs on XP, but I use Dragon NaturallySpeaking a LOT, as I have RSI. Version 10, Preferred.
This latest version is just brilliant. It's reliable, accurate and relatively easy to use, and a long way from those earlier frustrating versions. Once you get used to how it works your speed and accuracy pick up dramatically.
You'll need a good headset for maximum accuracy, and they don't come cheap: I use the Sennheiser ME3, with a little USB sound-pod: they're better than installed sound-cards, as they're not subject to so much electronic noise from all the other computer components (although when I trialled the version that Dragon sells complete with a bluetooth headset I had excellent results with the headset supplied, so perhaps that was only true of the earlier versions).
You can read about it all on my blog.