I bought my copy in 2008, and have received multiple updates for free. I compared it with Narrator and OS X's included text-to-speech, and immediately noticed GhostReader's superiority.
I liked Narrator's ability to automatically combine different voices, but the sound quality was inferior. You can buy additional voices:
I have not customized any GhostReader voices in terms of speed, volume, or pronunciation, but these features are available.
My complaints would be that the included voices are too few. For instance, only 5 US English voices and of those only one is an adult male. Not all sound great, and additional languages are $25
I typed some of Alex's speech found here:
Using Ryan's voice is a vast improvement, at least to my ears. It took me about 2 minutes to type the text and have Ryan read it.
Due to an earlier comment I also tried this text:
"Blowing in the wind I need to wind my clock."
The pronunciation of the word "wind" was correct -and different- in each instance. Try the same sentence with Alex ;)