I've got both an Apo-Skopar and a Red Dot Artar, both barrel lenses, both 24". The Artar is smaller, lighter. The Apo-Skopar is massive. Got them mounted for different cameras. Was wondering...shouldn't they perform about the same? (at similar apertures) Not done much shooting with each, though, so can't yet decide. Not trying to weed one out, please understand, just curious.
I have both a 19" RD Artar and a 45cm Apo-Skopar. The Artar is very sharp and contrasty, but somehow I like the image quality of the Apo-Skopar more. If I use the words to describe different wines, the skopar feels more full-bodied.
Can't answer directly, but I have shot a 300/10 Apo Saphir against a 305/9 Apo Nikkor. The AS is a heliar type like the Apo Skopar, the AN is a dialyt type like the Artar.
As I see 'em, the AN is sharper wide open and at f/11 than the AS, from f/16 down they're equal. Both are excellent lenses, one could be very happy with either.
I'm an insensitive clod, don't often see differences between lenses in what people call signature or rendition. I think you'd best answer your question yourself.