I've had my mustache(female), underarms, and bikini line treated so far. Mustache took 4-5 15 minute treatments and has been gone for 2 years. Underarms took 2 sessions at 15 minutes each (mind you I had very little underarm hair. And I am still working on my bikini line, about 1 inch on each side has taken 2 sessions at 30 minutes each.
The cost above is for everything I've had done so far, but both my practitioners I've seen have been doing the profession for 30+ years. The key is to find a person that only does electrolysis and masters the area of work. I guarantee the people who have bad things to say about it had inexperienced people working on them. It is not permanent if it isn't done right.
As for the cons, it is quite painful. However, the more it hurts the greater damage to the follicle, and the more effective the treatment, that's what gets me by!