I have a JVC RS520 I got for a couple grand from a guy who upgraded to an NX7 last year. Due to my room setup, I have two different screens to optimize the screen areas for different content. I have a 100" 16:9 screen and a 115" 2.4:1 screen. The 100" is from Elite while the 115" is from XY Screen in China. Both are electric and acoustically transparent.
Coming from a Panasonic ZT60, there was certainly a decrease in contrast performance, but you can't beat the image size. Going with a projector also gives me more flexibility in the size/position of my front speakers. If I had gotten a large TV, I couldn't have gotten the significantly larger speakers that I went with last year. Projectors are also multiple orders of magnitude easier to sell/upgrade since you can actually ship them for a reasonable price.
HDR works great, but only for the expanded color gamut. The super-bright highlights that the nicer Samsung and LG sets can achieve are out of the question for almost any projector at this point. You also really need to have a dark room if you want your setup to reach its max potential. So in my basement I blacked out the walls, ceiling, and floors around my screen. I also added black curtains behind it to reduce any reflections coming back, which is something that can be an issue.
I also had to buy a fiber-optic HDMI cable to get 4k60 with HDR to work because my receiver is on the opposite side of the room to my projector. Even the nice Monoprice "certified" cables couldn't properly transmit the signal over the distance I required. The cable was about $100 on Amazon.
Projectors also make noise, though the nicer ones typically make less than the cheaper ones. In low lamp mode, which I use for SDR gaming/movies, I don't really notice it. When I use high lamp mode for HDR or widescreen movies it can be noticeable in quieter scenes when you try and listen to it, but not enough for it to be a problem at all.
There also aren't any projectors, at least not at the high end, that have HDMI 2.1 or high refresh rate input capability. This means you're stuck at 4k60 as your max performance target. If you're primarily gaming on consoles, this probably isn't going to be a big deal as I don't see a lot of the next gen games going beyond 60 fps, but it's certainly something to consider if you're on PC.
As for what to look for when buying a projector, it really just comes down to budget. The gap between a cheap and nice projector is MASSIVE. It's so big in fact that I would say if you're not willing to lay down $2-$3k for a unit then you should just get a decent TV instead. The contrast performance ALONE is worth the jump into something like a nice JVC or Sony.
