Quote - "Using "shadow map-soft shadows", but the results may nopt be accurate for a spotlight, you'll need a fairly big map to get pleasing results ( check the auto size button, and limit the max size to 2048, if you go higher, there's no point using a map). This works well for a point light, should not be used for the sun."

Bruno, I use it for the sun as well. The render with shadow map is much faster than without it, even if the map is at 4096 (which is what I usually use).

Quote - "Or raytraced shadows with 5% softness added from the object properties panel. This will give you 100% accurate shadows, with physically correct blurring on the edges of the shadows the further away the shadow is from the lightsource, at the expense of longer render times."

Yes, especially because to eliminate the grain it's many times necessary to increase the quality sliders (either in the Light tab of the atmosphere, if it's the sun, or in the Volumetric tab of the light properties, if it's another type of light).

Quote - "As for 100% shadows, I rarely leave it at that, I go for 85% as well, and I never noticed noise due to this, would love to see an example, Artur."

I will try to create an example this weekend (I barely have time to Vue during weekdays).
Indeed, there is noise, especially on vegetation. I started suspecting this when I was working an aerial view of a mountain covered with trees. In the shadow areas, the trees were looking really weird. I set the shadow density to 100% and used sky dome lighting gain instead, and not only I eliminated the noise, I also got a much more pleasing result, visually speaking. Try it for yourself, you'll see. This might also depend on other circumstances (light model, etc), I'm not sure, so it might not be immediate to detect this, but it exists. Anyway, regardless of noise, it looks much better with sky dome lighting gain, IMO, and that's a sufficiently good enough reason for me to use it.