Eric1, I wish you the best on your date tonight!

I personally never compare other women to my exBPDgf, but that's just me. I agree with everybody that part of the appeal of a pwBPD is the mirroring (though most people also do this to an extent). Also as far as I can tell some people (not just pwBPD) "floodlight" you by overexposing themselves to you, making you feel like they are really letting you in. It is a way of short circuiting the usual get-to-know-you awkwardness most people have when they meet new people. You can feel like you had a very close connection after having such a soul-baring talk, but it's really a boundary busting technique to grab whatever empathy or feelings of closeness they need from you.
I do understand that I'm not immune to these types of communication. But I also am not really the kind of person who usually compares people and situations much. I do understand a lot of what drew me to my pwBPD is the intensity of the relationship at first, but I don't have any requirement for the other person to generate that "spark" for me. I guess maybe I am just happy to enjoy the company of another person who is simpatico because I generally am myself? That might not work for everybody else.