A few years ago I would have strongly recommended a projector for a gaming room, it's awesome gaming on a huge screen. However since 4K is creeping closer and closer, and 4k projectors are still over $8k without HDR, a TV is probably the better option.
This site does comprehensive reviews including suitability for gaming
http://ca.rtings.com/tv/reviews/by-resolution/4k-ultra-hd-uhd/best
http://ca.rtings.com/tv/reviews/by-usage/video-gaming/best
Are you planning to add a dedicated sound system too? Marantz has very nice amplifiers atm as well as Onkyo. I'm still happy with Yamaha. Getting a subwoofer and at least 5 dedicated speakers (preferably all the same) does wonders for sound. It can be expensive though, it's not unusual to spend 2 to 3 times more on sound than on the tv. Speakers will last you a whole lot longer. I'm still using my B&W 600 series from '95 and a Rel Storm III subwoofer that was second hand back then already.
Don't foget to add dimmers for the lights, gaming in low light adds to immersion imo and is definitely needed for HDR. HDR is meant to be watched at very low ambient light levels to be able to see the extra detail, especially with OLED. (is generally a bit darker than LED with much better black levels)
I'm not ready to upgrade yet, still waiting to see if 4K projectors will come down in price and whether there's any chance of them supporting HDR. It's hard to go back to a smaller screen, gaming at 92" 1080p right now.







