It only has a female voice.
Yes, I use Calibre. Yes, the Pocket Pro definitely has folder structure which is really customizable! This is one of its strong points.
To be honest, I have never used a Kindle to compare.
I can appreciate your careful analysis of features before buying a new device. I would recommend,
if it is possible, to also look at the devices you are deciding between in person. I know you can see the Pocket Pro in store at
Cartoys if you are located in USA near one of their stores.
Of course I am sure you will get lots of other replies to your questions here from other forum members as well.