Yes, sorta, well, I did for awhile.
I used iListen on the Mac, not Dragon.
Honestly, I'm not sure time efficiency is the best reason to get voice recognition software.
Voice recognition is some of the most sophisticated software out there, and it involves a good bit of work to learn the programs, and get them running right.
You have to actually train the software over time to recognize your voice. It's not like regular software where you just read the manual, learn what the buttons do, and then you're done.
It's actually similar to training a wild animal, a lot of repetition is involved, and you get bitten quite a bit.
I don't mean to discourage you, because those who master voice recognition are often very fond of their setups.
I just mean to warn you to keep your expectations realistic. For the first few months, it will probably cost you time, not save you time.
I just didn't have the patience for the training period myself. If I was going to do it again, I'd set aside an hour a day to work on it, and not expect results for some time. Just be patient, and whittle away at it, bit by bit.
I'm interested in voice recognition too. But for now, I'm hanging back, and waiting for that industry to mature.
I'm hoping they'll have it really ready by the time I'm too old to type.