This is all very subjective, so there's no 'right or wrong'. Here's my take:
I started with an RS400, and with the use of a Panasonic UB820, HDFury Linker, and imported custom gamma curves, HDR performance was adequate. But it left a lot to be desired.
I moved up to the NX7, and HDR performance was dramatically better. I had some time with both in my Theater to A/B them, using the same content, at the same time, and the difference was in fact 'night and day.' I showed this to my very non-technical wife, without saying which was which, and she immediately recognized the improvement.
This is where the somewhat subjective part comes in, but even with the NX7, I still had to tweak settings at times for different movies. Not a lot, but enough that it bothered me. And even some scenes within a given movie looked like they weren't optimally shown, relative to other scenes. Overall it was still quite good, but I still felt that I wasn't getting all I could out of my NX7.
I next got the DCR Lens, which added significant overall brightness, and provided the ability to instantly switch from 2.35:1 to 16:9, rather than using the 'Zoom' method. This was a very nice improvement, providing much more light to enhance HDR. But with it came some negatives. Specifically, it handled 2.35:1 through 2.40:1, and 16:9 Aspect Ratio shows and movies just fine, but with 'in-between' content, especially 2.00:1 and 2.20:1, there weren't any good options, and compromises had to be made to watch them, neither of which I really cared for.
I frequently use Subtitles, and with 2.35:1 content, with the DCR, they were often either partially, or completely cut off and not usable. This was mainly for streaming content, as my UB820 allowed me to shift Subtitles into the content area, avoiding this problem.
My next major upgrade was going with the madVR Envy, about 3 months ago. This has been a huge improvement, in every respect. It now seamlessly handles any and all Aspect Ratios, and has a newly developed ability to handle Subtitles, which works extremely well. And this is all handled automatically, no button pushes required, no user action needed.
And with its DTM, everything looks fantastic. I no longer feel any need to tweak settings, and can just enjoy the view.
Regarding getting the DCR or Envy (or Lumagen if that's the way you lean), that's a tough choice. Each is excellent on its own, but the combination, the synergy between them, takes my Theater to the next level.
Regarding NX9 vs NX7 + one or the other DCR or Envy/Lumagen, that's also subjective, and dependent on what one is willing to spend. For me, I chose the NX7 with the idea that combined with the DCR shortly after, that would give me more bang for the buck. In retrospect, I'd make the same choice. And as I said, when I then added the Envy, it took the overall theater experience to the 'next level.'
This is saying nothing negative about the NX9. In fact, if funds were unlimited, I'd get the NX9/DCR/Envy and be quite happy. But for me, I'm extremely happy with the performance I'm getting using the NX7 instead, feeling it gives me the better bang for the buck. But once again, this is a personal, subjective decision.
