Interesting -- how was the quality? In my experience, the machine readers aren't 100% comprehensible; you always have to stop and look at the actual text and it becomes hard to get much use out of it if you're truly on the go. This is never the case with human read audiobooks, which is why they are so useful.

Conveniently, I wrote on that exact issue too: https://www.twilio.com/blog/2013/08/the-pronunciation-challe... (It appears some of the Soundcloud links are broken, but check out my account there for the full samples.)

Very cool.