Sennheiser 6XX or 660S?

The main use of the headphones will be for gaming. I am currently using the DT 990 Pro's with a Jotunheim but find the 990s uncomfortable. I have heard that the Sennheiser 600 series is known for comfort and large sound base. Is it worth spending a couple hundred more dollars for the 660S if my main use for them will be gaming? Or will I get similar performance from the 6XX's?
I need your help and advice especially since I have never owned a pair of 600s or 650s.
Thank you.

May 30, 2018
The HD 6XX is good for the price, the HD 660 S is worthless. Also if you don't listen to much music and are 99% focused on gaming then the Jotunheim was a wasted expense and so is any headphone over $200 or so.
Get the AKG K7xx, it's so often an active drop. Better for gaming than the HD 6XX due to its larger sound stage, and it's lightweight with large enough memory foam pads and a suspension headband on top of it so it's comfortable.
Nov 19, 2018
As an ex-professional gamer, I'd have to agree with this, as much as I prefer the 6XX for music the K600 and K700 series are better for positional audio in games, even if they'll not win any awards for amount of bass.
May 20, 2018
Take advantage of the balanced section in the jotunheim as it is quite powerful and get the 6XX. U will not regret it!
May 20, 2018
I'm not a gamer, but if it was me I'd go for the cheaper option if my primary use was gaming. All the 6 series headphones are quality, but if you're not listening to music I'd save the cash and go with the lower cost option.