TechPowerUp posted a review on the Sennheiser GSP 500
A quote from the article:
Open-back gaming headsets are few and far between, but Sennheiser didn't forget about users who prefer them over their closed-back brethren. Let's find out if the Sennheiser GSP 500 offers enough to justify its hefty $230/€229 price tag and if it's a worthy replacement for the company's excellent Game One gaming headset.Sennheiser GSP 500 Review
Sennheiser released two new gaming headsets in 2018—the GSP 600 (reviewed here) and, shortly afterwards, its open-back twin brother dubbed the GSP 500, which I'll talk about in this review. They serve as replacements for the famous Game Zero and Game One headsets. Meaning, if you're after the best gaming headset Sennheiser has to offer, the GSP 500 and 600 are the ones you'll choose between nowadays.