Yeah I agree, to which system you go for has a lot to do with the space you have around your seating area. The closer to the screen and the speakers the worse it looks and sounds. I used to fit av systems for a living. The 110" screen I use is the biggest I'll have in my front room. In the past I had bigger and it gives you the feeling of sitting on the front row of the cinema you just cant take the whole picture in. And with the speakers if your too close you hear the speakers if you know what I mean, I feel you shouldn't be able to pinpoint were each sound is coming from it should float around you. In my 6.1 system I do have the middle center speaker directly behind me but I have it's volume set very low so it blends better with the rears. It really can make you feel like there's a vastness to the space behind you. Lord of the Rings comes to mind as you do actually hear more with than without.

With the 4K I've read it can look like you looking through a window but only with native 4k material otherwise there seams not be not much of a difference between that and 1080p. But I haven't had the pleasure of seeing one yet.