Wow. DS3 is currently my favorite of the bunch, though it's really hard for me to decide which of the 3 stories I liked the most. I think Dark Lady I has the edge though, because I learned the most about Silvio in that one over the others. Not in the respect of what he's capable of doing to accomplish his goals, which is significant when he's up against 4 Russians at once, but in terms of what he's capable of feeling too. He's neither completely heartless nor a psychopath, but he is focused and determined, and even a bit empathetic. I would not say that he's not completely sane, but rather he's not completely whole - broken, to an extent. 
 Dark Lady II was a nice, short vignette where Silvio hooks Stefano just a little bit more. Definitely sexy. 
 Dark Brother was a bit mind-blowing. I liked Franco, Silvio's older brother (the middle of the 3). Even though we just met him, I was able to relate to him in that short period of time. Silvio is a definite weakness in his armor. Franco's motivations and hang-ups made sense, as did the ways in which Silvio ignored or overrode them. (view spoiler)[I am actually surprised that there wasn't a content-related spoiler warning specifically for "incest" in addition to "heavy kink" though. Not that I minded at all, but that doesn't exactly come to mind when I think "heavy kink". I bet some will be shocked. (hide spoiler)] I also liked Stefano's treatment in the whole scene. He's an empathetic and very likeable character, even more so now in my opinion. Maybe that will be different in the future if certain things come to light. Who knows? 
 I can't wait to read more about Silvio. He's an absolutely fascinating character.