I am in the same boat here. A Nikon D5 is my 'go-to' camera with a similar resolution as the SL. But I have to admit to prefer the look of a (36-to-21) Mpix or (45-to-21) Mpix down sampled capture in some situations. And with the added D5-features the D850 is a very well featured/balanced camera. Just my thoughts on this.I will come back to this thread with some more thoughts. At some point, MP count becomes nearly irrelevant. If for you that point happens to be 24MP or less, then I believe the SL is a great option. For me, 24 is good enough for most things, but getting over 30MP adds a smoothness that isn't present at 24 in *my* humble opinion.
Regards, Udo