I've used Fuji equipment for my digital photography since 2013. And I've tried to switch to a full frame camera system a number of times. Each time the expense didn't justify the slight (if any) increase in image quality, and up until the current crop of Sony cameras the user experience was always much worse. Nikon for example still insists on cropping the raw files when you shoot in anything other than a 2:3 aspect ratio, and don't even bother looking for a manual focus distance scale anywhere. 

          The Sony A7RV is a full frame camera that I can live with. There is an increase in IQ, but more importantly it just gets out of the way and makes great images. It's very competent with few "holes" in the interface. (I actually found one the other day: you can't ask it to use its fancy AF system with the self timer. When you push the shutter button and the self timer starts, whatever it focused on when you pushed the button is what you get. That's an omission of programing, nobody thought designing it bothered to think that maybe somebody would want to use the self timer and have the "smart" camera continue to look for a face that might pop up from behind the camera.)

          But that's a very minor niggle compared to where the A7RIV was. The A7RV is just boringly competent. Which is actually a good thing. And then there's the lens selection. It's actually hard to choose some focal lengths because there's a dozen options to choose from! Spoilt for choice. Preliminarily I have the Zeiss 24-70 F4 which is an old lens from the beginning of the system but strikes the right balance of quality, price and performance for me. This lens has some mixed reviews, but I must say the made in Japan examples I've used and seen have all been great. The other budget starter lens I got was the Tamron 70-300mm which is a decent lens for the price. I also have the Tamron 20mm, the Samyang 35mm (not recommended, too cheaply built and not that sharp, fine for video though) and the Sony 50mm 1.8 which is sharp but very slow to focus. I plan on getting the awesome Sigma 14-24mm and 100-400 again, Something 24mm, and the Sigma 90mm, as funds allow.