I reviewed the Rig 600 on my personal site over here:
Plantronics RIG 600 Gaming Headset Review with Mic Tests - World Bolding
Sometimes as I'm walking through a Best Buy, I see an audio product I don't expect to find there, and BAM here we are…
It’s a re-badge of a much older RIG design. It has almost no sound isolation and a much different style of build, but the sound quality is in the same ballpark.
I’d personally lean towards the look and feel of the 500 Pro if I was forced to pick between these two based on my own tastes.