The transcription is very good. They really offer a heap of languages, dozens. I couldn't count them, but I guess, quite the most. Including variants/accents.
The first transcriptions worked well.
So far I had Spanish and English videos (English with french accent). The transcription worked well.
Important to know:
It's a dynamic transcription with video. If you click a word, the video jumps to the right time.
Afterwards you can convert to subtitles. And you can translate the text/subtitles. Translation is beta, but includes the most common languages. English, Chinese, Spanish, French, German, Italian, Russian, Japanese and more.