If you watch few actual discs and most of your viewing is from streaming then the obvious choice is the NX5 as it's the only one with Tonal Mapping for everything, something MadVR can't do and the Sony is probably no better than the x750 at HDR plus you would be taking a major hit in black levels with the Sony.I currently have a JVC x750.
Been thinking it's time for an upgrade. I've found a decently priced Sony and have been looking at the nx5 for ease of HDR settings.
Room is dedicated and very dark.
Sources are an Nvidia shield, odroid c4 and PS4 . I was watch very few physical discs but have a Panasonic spinner for tone mapping.