when using the rgb profile as an output profile you recommend to use a generic profile,
such as sRGB or a monitor profile, right? is the sRGB profile recommendable in general for
sourcemapping with output profiles or do you also have good experiences with other profiles
such as ColorMatch (using the same D50 illuminant) or AdobeRGB as well?
It depends on your intended use. You need to think about the kind of color spaces (gamuts) that you will be feeding into the output profile, and choose something representative as the argument to -S.
Many people feed "RGB" images to printers using perceptual or saturation intent, and sRGB is a pretty generic RGB space that puts the gamut mapping in the ballpark for common use.
If you have more exacting requirements than that, then you should choose the actual colorspace of the material you intend to output as the argument to -S. If there are several different colorspaces, then perhaps you need several different versions of the output profile, each with a gamut mapping optimized for that source.
Better quality can be had by using icclink -G, and device links of course.