Its not perfect and it may get a word or two wrong, but I just downloaded the app and spoke a good 30 seconds of text, probably ten to fifteen lines, and it got everything right the first time for me! I just dont like that it is not integrated into the iPhone, you have to click the app every time and add the contact, if it was integrated and you had a button to reply via text from your regular messaging it would be perfect!!!
Rasta shane about Voice SMS : Speech to Text