For a long time, I pretty much wrote off any band that was female fronted because none of them had ever grabbed me. I'm guessing it's because many of them stay in that SUPER operatic style/range, which isn't for me. Many of the bands are also pretty cookie-cutter at this point and are basically doing the same thing as 1000 other female fronted bands.
One of the bands that finally tipped it for me was Epica, much heavier than expected and Simone Simmons doesn't go full on opera all that often. Triosphere, Collibus, and Unleash the Archers are some other ones that helped me bridge the gap and I think it's because they mostly stay more in that a mid-range, almost "rock" like style.
Now I don't bat an eye whenever I see a new female fronted band release something. I just check it out and see if I dig it.