If you scroll down the page you can play a whole bunch of examples and do your own comparison. Some of the voices are remarkably lifelike. The most lifelike o

If you scroll down the page you can play a whole bunch of examples and do your own comparison. Some of the voices are remarkably lifelike. The most lifelike ones are IBM Watson (which I found a bit surprising to be honest), Google Wavenet and Azure Neural. The latter two seems to be based on some sort of AI technology to make the voices sounds more natural. Amazon Polly does not yet seem to have AI powered voices but presumably they are working on it. Text to speec has come a long way since the days of SAM that's for sure.