No worries, I didn't want to start an argument!
I really like both inks, but blue black gets more use as it is a real workhorse kind of ink.
Although I have to say, that (at least with my bottles) there are no subtle differences, the inks look completely different. I can not see similarities between them (other than that they are both called blue black).
I think my ink color comparison skills are not so good cause I only see subtle differences.
maybe its the case that some people have a particularly good eye for inks, just like some people have a particularly good ear for music. Maybe its something you are born with??