we do it for a lot of lawyers (assuming you are one by the name lol)
One client started using Dragon, but not for mac. From what i gather, the more you use it the better it gets.
You can also let it "read" your entire email list to see what words you use often.
Now, the fella i heard use it had a thick nola accent and had a few problems, but the big annoyance i saw was the voice commands to go back, delete, change, over and over.
I have been wanting to look into/experiment with Copy Talk. Where you record and upload what you want typed and it gets typed for you (enter on phone,etc) copytalk