My favorite CSN/CSNY tunes have always been Crosby's. His distinctive melodic sensibility and fondness for open tunings on big 'ol Martin dreads has a lot to do with it. IICORMN is one of my favorite albums of its genre.
As to his personal fallibilities, well, we've had discussions here on this topic often enough to suggest that great talent and less than great character are not exactly a rare juxtoposition. But this is not only evident in the arts; it's a paradoxical aspect of being human. I'm not defending anyone's bad behavior or suggesting how anyone else should judge such individuals. I will say that I believe it's unrealistic to assume that anyone who is highly accomplished in a particular field will necessarily be virtuous as well.