In the S1Rii I am very interested in the 14 stops of dynamic range and its behavior in terms of noise at high ISO. Because for me this is much more important than the rolling shutter or the speed of the camera in general.
For me, as a Nikon user for years, an alternative to this camera is the Nikon Z8, but reading people's opinions on the Nikon forums in Spanish (nikonistas.com), I think I am going to prefer the S1Rii because of opinions like this one (from Setnakht) about the Z8 that I copy and paste translated:
"A little down with first impressions:
Hello,
After completing my first two basketball games with the z8 combined with the 24-70 2.8 z and the 70-200 2.8 z, the truth is that I have mixed feelings. I come from a lumix s5 which I sold before having the z8 (before I had the z7ii, d4, d800, d810, d700, d3s...) and I was badly surprised by the noise in the photos. Starting from the basis that the matches were on fields with a dire light of course and that has a lot to do with it. The first match I shot at ISO 3200 2.8 1/1250 and the second at ISO 4000 2.8 1/1000. It is true that in this second match, despite seeing the exposure meter it told me that they were underexposed, I thought that when I raised the exposure the Lightroom would not be serious but I have already seen that no, that a lot of noise comes out. (...)
It is clear that for those ISOs the z6iii would be better for me but I also do birds and surfing and the 45mpx and the cropping is that for me it is everything. I will have to sacrifice one thing for another. Of course, for the next one I will use more ISO, for fear of not going above ISO 4000, the truth is that I have found a horrible noise when lifting".
I have seen many opinions like this on that forum. Here another one (from Longimanus777) in the same thread:
"I had the same feeling when purchasing the Z8, I wrote about it at the time when giving my first impressions in the general forum of the Z8, it came from the Z6II and it was and continues to be for me, traumatic in terms of noise.
There is no solution, this camera generates a lot of noise, in my opinion (I cannot compare because I have not had them simultaneously) much more than the D850.
The only thing I do is that even though I am at low ISO, I give the lightroom AI noise reduction and in the field I usually underexpose a little before overexposing.
I already said it, I wouldn't buy it again, if I hadn't rushed it, I would have the Z6III now.
Otherwise it is a very good camera, but the ISO issue is something that I usually take very high when photographing mammals".
These are opinions from Nikon users, not Sony, Canon or Fuji fanboys trying to bash Nikon.
I'm going to wait for opinions like these from users of the S1Rii to decide if I buy it, but I'm in no hurry for now. I certainly don't mind if the S1Rii has not a stacked sensor. For me is more important the DR and its behavior in low light.