The BAT VK-75 will offer a sweeter mid range and more of a real sound to the system IMO. I compared the VK-500 to a BAT VK-75 with Audio Physics speakers with the BAT VK-50SE and VK-D5SE a few years back and would have easily picked the VK-75 over the VK-500 and VK-6200 (running 2 channels).
Happy Listening.
Happy Listening.