Has anyone tried Natural Reader 3.0?

I downloaded this text to audio program for my Macbook Pro because I found the British female voice to be much less robot-y than any of the voices on the built in text to audio program on the Mac. But the Natural Reader 3.0 has all kinds of problems. It quits unexpectedly, you can't upload files from your computer, and the "save an audio file" function does not seem to work. I'm wondering if it is just not really compatible with the Mac. It seems to be a Windows product mostly, with the Mac version an afterthought.

Has anyone used this with any success. If not is there a recommended text to audio program?