Having been at CEDIA yesterday, pretty much every demo space had a "4K" projector (most aren't native or "true" 4K) with Dolby Atmos.
Here is the big stuff in relationship to 4K.
You need a very large screen and/or sit fairly close to the screen to really benefit from 4K. That means either a super-sized flat panel (I saw a 16:9 that was a massive 98" diagonal, and a 21:9 extra wide that was 105") or a front projection system with a good sized screen around 115" or larger.
With that said, most of the 4K projectors have other enhancements and hardware to make for a brighter image with better contrast ratio than their lower cost 1080p brothers. So you will still get a nice picture, even if you don't notice the increased resolution.
I did see 1 projector that was actually 4K vs. all of the "shift" technology using 1080p panels and such, and honestly, the "shift" technology looked better than the real deal. I started asking why, and it is because there have been a few years of products in the "shift" or "fake" 4K vs the limited products and experience with actual 4K. It was also talked about in a presentation that it is easier to fool the brain into liking a faked higher resolution than a real one. Not sure of the science behind that, but in the demos I saw it was true.
Now, like Michael says, people would probably do much better to get their displays calibrated than it would be for them to jump to 4K. I noticed a high improvement in my JVC RS-45 projector when I calibrated in a couple of years ago, and while it is probably due for a refresh (since the bulb dims over time) but the picture is so darn good thanks to the calibration. It was honestly like getting a brand new projector again after I calibrated the already amazing picture.
Most people are afraid of the sound of calibration, but you really can do it for about $100. No, it won't be as good as spending $300 or $500 on a meter and a chunk of change for software, but $100 would get you a basic meter and you can use free software, and then follow step by step guides to do the calibration. Of course most meters work with TVs OR projectors, but not both. I think that I spent a couple of hours doing my calibration because I went through the steps once to get the idea of what needed to be done, found out that I made a few mistakes, but got those corrected the second time. I was all gung-ho to calibrate more stuff because it was such a success.
I can't imagine what some of the auto-calibration boxes or a professional can do if I made a huge improvement on my 2nd try.
