Out of the three women's named thrown around this thread, Whitney Cummings is the worst, as in she is a truly bad comedian.
Silverman I don't like, but I wouldn't call her a bad comic.
Schmuer I don't like and tried to get into her stand-up, but she's the best of the three by a bit of a distance.
Another comic who is way more popular (not very, but somewhat) than her comedy dictates is Iliza Shlesinger. I've watched both her specials and I just can't. Same with Chris D'elia, can't stand dude.
If I had to have a list of simply "female comcis" Maria Bamford is by far my favorite; granted, not for everyone, but I think she's weird and absolutely hilarious.
Maria Bamford & Chelsea Peretti >