I recently purchased the S1Rii after previously owning the original version. I returned the camera as the blackout from the EVF wasn't much better over the MK1, it's really noticeable compared to the Z8. I found the S1Rii files excellent and sharp using the 24-105mm kit lens . Also, with the kit lens the coating was terrible to keep clean and it just captured dust.
In summary, it's an excellent camera if you can live with the EVF blackout and I would say IMO the Panasonic was my favourite camera to use file wise. So if you have the itch give it a scratch but with a company who has a great return policy.