I think they are pretty much the same dragon/viavoice - a lot of it has to do with a good mic and the readings to train it. My old Via voice for PC had a setting to continue to train during use - you could add words that it would have trouble with as you go along.
- I know Victoria uses dragon , DiMarie - i think.
quite a few on the sorehand list too
http://www.ucsf.edu/sorehand/#RESOURCES
http://www.out-loud.com/