It could just be a matter of opinion, but I prefer both Google's unit selection synthesis, and their WaveNet synthesis. The prosody in Apple's latest method is

It could just be a matter of opinion, but I prefer both Google's unit selection synthesis, and their WaveNet synthesis. The prosody in Apple's latest method is still annoying, nowhere near as good as the Google models of 2015 and 2016, and not remotely comparable to the WaveNet models. Apple's change in voice talent is an improvement though, and they may have more units than before, which is helpful. I believe their model also works offline, which is a huge plus (though I think Google's prior model works offline as well).