I have mixed feelings about this new Sony A7R3 release.
There's some good developments in there, but its the same sensor as the II, so ultimately, unless you need 10fps, or slightly improved eye focus, and a joystick, or shoot still lives with multi shot, then, really... save your $.
Sony seem to have forgotten how their camera designations divide up, the A9 is for sports/speed, the 7S is for low light and video, and the 7R is the ultra high megapixel one. Leaving it at 42.5Mp (even multi shot images are still 42.5Mp after processing) for a 3rd year of life seems like they forgot what the 'R' nomenclature is for! It is not for people wanting 10fps, or needing 32,000asa - it's about the ultimate quality resolution Sony can eek out of a sensor. Thats why people choose the R over others. They forgot that or, more likely the next generation 60Mp sensor was not ready, so they're distracting us with bells and whistles from other models, in the meanwhile!
Oh well, Hasselblad and Fuji can breathe a sigh of relief. Their MF offering are good for another year. Happy for them, and us, as that means they will survive into a 2nd generation at least.