Having had this tab opened for what seems like forever, I finally got around to running some tests of autoEdit 2, an open-source automatic transcription tool (automatically creates a text file from a given audio or video file). This tool only runs on the Mac, and there are two flavours, if you will. One, Gentle STT, runs completely on your local machine and costs nothing to do transcriptions, but it's not the best at it. If you have very clean audio you can probably get by with this, but I found it pretty sketchy. The second makes use of IBM Watson's Bluemix service, and for me was both faster and much more accurate. With Bluemix you get 16 hours of transcription free per month, but anything more than that will cost $0.02/minute, which is still pretty darn reasonable, IMHO.
One of the things that slowed me down was a lack of troubleshooting documentation. The software itself is pretty straightforward and easy to use, but the first step of plugging in your Bluemix API key is a bit sparse. I put in the wrong credentials, and autoEdit took them without complaint, and pretended to work on the transcription for a long time before I decided it wasn't really doing anything. I couldn't find anywhere to re-enter credentials, so I ended up uninstalling and reinstalling the program.
I'll see if I can contribute to the documentation, but for now, once you've got your free Bluemix account, you want to scroll to the bottom right of the main account page and click on the Create button.
On the next screen, choose the 2nd "tab", "Service Credentials", and then View Credentials. That's where you'll find your API username and password. Be sure to enter them in the correct order within autoEdit; the username, at least in my case, was much longer, and is presented 2nd on the Bluemix page :-/
That's all from me. It does work quite well, and if you need to create a written transcript from a video or audio file, I think this is a pretty darn good way to go!