In my experience, Google's API completely fails when any slightly unusual vocabulary is involved (e.g. in this instance, grandparents talking about their past jobs), and tends to just silently skip over things. Amazon's wasn't much better with vocab., but at least didn't leave things out, so you could see problems. I don't have experience with any of these others, but I think for my purposes (subtitles for maths education videos) no one will have made an appropriate model yet.