I bought the 599 like 1.5 years ago. The 599 is on sale several times a year. Atleast here in Sweden. Something to consider. I wanted them also because I read they were a bit warmer. They have a little bump in the bass for an open back. I mostly use them for gaming honestly though with the Series X and using the Dolby atmos app.
In my experience so far they sound natural, pretty crisp and full. I switch between them and hyper xcloud alpha. I like both of them in different ways. More oumph and closed off with the Alpha and more crisp and detailed, less hot on the ears and I can hear if someone knocks on the door or whatnot. I like this combo.
Peace of mind.