Maybe the Ranger which is in between. I think the Ranger is the same as the Hero but without the lighting effects. I've tried to find out if the A/Pro-Gaming has the same VRM as the Ranger/Hero, but I have yet to find a definitive answer. I would get the Pro-Gaming over the Z170-A for the better audio and extra two rear USB 3.0 ports.
http://www.asus.com/us/site/motherboards/Z170/compare/
[strike]I think your choice should be between the Pro-Gaming and the Ranger.[/strike]
More research reveals a definite difference between the VRM's of the Pro/Pro-Gaming and the Hero and all of these are a step up from the Z170-A. As far as the Ranger is concerned, Anandtech states:
The Ranger fills in at the bottom of the ROG stack, but still comes with a number of important features. If anything, it seems to mirror the Hero without the large rear panel shield, use a different style of power delivery chokes and comes without an RGB LED in the chipset. Avid onlookers will notice the adjustment of the reset button to a simpler design and two fewer SATA ports as well.
You get Q-code on the Hero/Ranger, but Q-LED on the others. The code gives you a malfunction code when something doesn't work, while the LED just blinks next to the malfunctioning part without specific information.