I have an S3 2000 and a Leica to compare with it. The Nikon is 1:1 viewfinder, which I find a little better to use than the Leica. Rangefinder patch edges are indeed less distinct on the Nikon, though not fuzzy after cleaning. Rangefinder contrast is better on the Leica M.
Things rarely mentioned are how the cameras are to hold and wind, and focus ergonomics. In general, if you have large hands, you’ll feel the edges more on the Nikon. Film winding fairly close feel, though film loading the Nikon is easier. Some don’t like the focus wheel on the Nikon rangefinder, though it’s super convenient with some lenses. Overall most Leica M bodies feel smoother to operate than the Nikon S3 2000.
So, it sounds like I’m dissing the Nikon S3 2000, but I actually really like using it. That 50mm Nikkor S f1,4 is quite amazing in rendering, and I feel that’s the reason to own one.