It was the new A7RivA I tried when I was sorting the Wex/Fixation saga.
I really couldn't believe how far its moved on. I never encountered the A7r4 but the A7R3 etc and older running workshops and honestly I really didn't rate them. Yeah they're the future etc but I prefer mature products - I'm not an early adopter.
This thing though is the Z9s sensor guard (I hate sensor dirt and anything that reduces it I see as worthwhile) and shutter mechanism (or lack of) away from being "the finished article". It seemed more robust feeling also. Ideal basically.
@Steelo should buy the A7r4a without a doubt or hold out for A7rV which will probably have these features