Last I checked, there was a free Dragon Dictation app for the iPhone. I tried it out that way to see what I thought. It could be a paid app now, but I am guessing it was free to allow users to consider purchasing the real program.
It was alright, and I have heard training comments similar to above.
Not sure if this was already addressed in that link to another discussion on this software, but one concern as writers should be the difference between how we write and how we talk. Linguistically there are many differences, and I would carefully consider that when deciding the program's use (eg. using it for an email vs. for a novel).
I would *
never* ? depend on it for writing books. Or at least, if I did, I would want to carefully re-visit it "visually" later, in order to be sure that while speaking, my real voice came through (pun not intended, but I'll take it).
Edit: to add that perhaps *never* is too strong a word- I love typing on my iPad, so how could I say for sure that "thumb" typing is not also modifying my voice
... But either way, it is worth at least recognizing the difference that may be seen in spoken vs written words...