I think one important aspect is while humans miss words, they often get the sentence meaning correct. When computers miss words, they tend to substitute words that sound similar. That's readable if you have time but not necessarily as a stream of text going by...
The character on the screen said "Hello", the English subtitle said "You good." Which would be the literal translation of nihao.
I don't think that is possible. Like, worse subtitling isn't even an option.
http://www.nbc.com/saturday-night-live/video/british-movie/n...
So if this speech recognition is for creating a transcript for humans, this (in my uneducated opinion) isn't as good as humans do, at least not yet.
Being Microsoft, I'm sure the place is diverse, but there's no mention in the paper on accents or dialects that I can see (might just be missing it).
On the CallHome dataset humans confuse words 4.1% of the time, but delete 6.5% of words, most commonly deleting the word "I".
Their ASR system confuses 6.5% of words on this dataset, but only deletes 3.3% of words, so depending on how you view this their claim about being better than humans isn't definitely true, if you consider the task to be speech recognition, rather than transcription.
Also, while the overall "word error rate" is lower than humans it's not clear if this is because the transcription service they used is not seeking perfect output, but rather good enough output and the errors the transcription service makes may not be as bad as the errors the ASR system makes in terms of how well you can recover the original meaning from the transcription.
It's clearly great work, but reaching human parity is marketing fluff.