Cool! Which STT library/service are you using? How are you finding the error rate?
Currently I'm using Google's Speech API. Based on my tests, they have the best transcription results by far.
I experimented with a few others (IBM, for one) and found that while the coding was easier (because they allow a wider variety of audio file formats), the results weren't as accurate. Google, on the other hand, is fairly picky about what types of files can be processed - this is also probably what makes them more accurate. So in the background, there's a fair bit of audio transcoding that goes on before transcription.
What do you mean by error rate?
By error rate I mean Word Error Rate (WER): https://en.wikipedia.org/wiki/Word_error_rate
Based on my own personal experience however, I would say I've gotten around 85% accuracy.