The 650 has about the best timbre and tonality of any mid-fi headphone but the smallish soundstage, mid bass hump and lack of air in the treble make them 'meh' for gaming. They're 9/10 for vocals, jazz and some classic rock though. On the downside they need an amp. The better your amp/DAC chain the better they sound. All in all I like the HD600 better.
But the OP mentioned gaming. And the cheaper but just as 'good' Fidelio X2 at $150 is better for gaming. It has a HUGE soundstage. There's really not a better value that I've found in the headphone world. They don't roll off in the bass like the Sennheisers and have actual sub bass. They maybe lack a little air in the treble but it's about the same as the 650s. They also don't need an...