I AM A BIG FAN of audio transcription services and the combination of machine learning and human curation inside Rev.com is so very helpful.
I've used Rev.com transcriptions several times and now I'm starting to set aside a working budget that allows me to quickly use transcripts arising immediately after getting a podcast interview. We did that with the Youth Media Team interview of Sabina Higgins and discovered that Rev.com's transcript was generated faster than a YMT.fm team member could blog about the interview.
I'm looking at other cognitive services, notably Cortana on Azure and Google Voice directly on a handset. The Google option is limited by the memory of the handset used to produce the content. There's more of an opportunity with Cortana, once I set aside the time and head space to set up instances with Azure.  I also need to explore the API option with Rev.com.
As expected, the best quality transcripts come from the best inputs, something that experts emphasize with their advice. When out and about with the Youth Media Team, I carry a small case with high quality microphones.
The best portable mic for our purposes is the ATR 2100 USB microphone (pictured below).  It snaps right into the lightning port of our iOS recorders.
We've come a long way from the Sony ICD MX-20 digital voice recorder. People still visit my InsideView blog looking for Sony Digital Voice Editor Software.  That suggests there are pockets of transcriptionists working to produce text copies of medical reports and architectural surveys, just like we encountered in Ireland more than 15 years ago when Sony ruled the top end of handheld dictaphones. Nowadays, there's an iPhone for that.
But some of the best advice is timeless. "A big misconception about voice recorders is that they can transcribe your voice into text on its own. If you’re looking to do that," writes Jennifer Finney, "You’ll either need to buy expensive computer software (or a very expensive recorder) to do it yourself. An alternative is to download Rev’s free Voice Recorder app, which allows you to record audio from your phone and place an order for a transcript with a single tap". 
- Speech is a Cortana Cognitive Service.
- See an entire photo album dedicated to Bernie Goldbach's podcasting.
- You can download Sony Digital Voice Editor software here (38 MB zip file).
- Jennifer Finney -- "Important Things to Look For in a Quality Voice Recorder" on the Rev.com blog, October 16, 2018.
[Bernie Goldbach teaches creative media for business in the Limerick Institute of Technology. He also advises the Youth Media Team on their technical requirements.]