So from what I understand the main difference is that the borderlines failed to cope and build proper defense mechanisms and therefore suffers deeply inside while the narcissist built proper and reliable self defense-mechanisms but suffers the same abondonment issues.
Its quite a mind paradox because the N has the B "pathological child" but different mechanisms surrounding such well, I don't really know you get the idea i'm no psychologist lol.
So who 'wins' at the dating game, the narcissist or the borderline?