I think the voice for the samples in your link still has the problems they talk about in that article. There are noticeable blips in the speech that sound unna

I think the voice for the samples in your link still has the problems they talk about in that article. There are noticeable blips in the speech that sound unnatural, particularly when certain sound combinations are used. The very first sample with "Bruce Frederick" is clearly off. The intonation and timing between the end of bruce and the beginning of frederick is... mechanical. There's a similar problem in the OPs link with the non-wavenet English voice 1 when it says "Wavenet". Those issues are much less apparent in the wavenet voices. Timing problems are less noticeable, intonation problems are less noticeable. Frankly, the voices there sound VERY good, compared to anything I've heard. That said, I completely agree that there's not enough samples there to make any real judgement.