I agree with what EKaterine is saying - it is a realistic look at the lifting, and women need to know it. The other realities are:
-A woman adding 20 lbs of muscle... is a highly unrealistic proposition. While 20 lbs of muscle is no biggie for a men, adding that much muscle for a women without drugs is basically impossible, even if she was untrained!
-when you are talking BF% vs definition it's not like different rules exist for men and women. Picture a man at 30% BF. I would never call him athletic, even if the male advantage make some of his muscle stand out (likely on his limbs). You would expect a gut and soft body, including men-boobs on someone with that level of fat. The SAME occurs in women. There will be a coat of fat that Ekaterine mentioned.
-There is no law that makes you perceive a woman at the same level of BF% as a man as leaner because it's "fair" to expect the woman to have more BF
-in the ideal world, I am sure most of women picture those extra % going right into boobs. Like that happens so often! Those extra % will go where it makes you look fatter - thighs sides, stomach and muffin top.
-quite a few articles state now that lifting caloric afterburn does not happen in women the way it does in men.
-Muscle that tend to grow better on women are lower body muscles in a quad and less in hamstring, and upper body changes very little compared to that. Having heavier leg is normally not a goal for women (men tend to want that more for 'chicken legs' syndrome)
-there is a psychologically challenging thing with the weight lifting, because everyone gets wrapped up in the BIGGGER, BIGGER and BIGGEST lifts. So a woman in the gym will see every day the men that bicep curl what they deadlift. And the stalls will happen early and forever, and it will be far more pronounced failure than getting in 18 reps instead of 20 on the military press with 10# dumbbell in the racket of a Boot Camp class.
Weight lifting solves no real advantages in comparison to cardio and light weights when it comes to aesthetics. It is neither shorter time and energy commitments, nor the results are visibly different in a normal woman ('cause you know, 3 lbs of muscle from barbell doesn't look very different than 2 lbs of muscle through a Boot Camp). Women gain misly amount of muscule no matter how they train compared to men.
And, I am sorry to say it, but in my experience, there is no significant difference in the achievements of the women who are not athletically and genetically gifted in building their bods with heavy lifting vs cardio. In fact, the most successful bodies I see in the gym belong to cardio/light weights crowd, not heavy lifting crowd. I mean, there is this girl in the gym who lost her weight about the time I did. She does double cardio limit of 30 min on the machines every time she trains and some light stuff with DBs. I was lifting all that time. She sure never changed from her slender new self, while I went through endless cycles of fatter when I am not watching, and slimmer when I ground my teeth and starved. In the end I have a gut and better shoulders, and she overall looks like a goddess and I am certain did not bust her wrists every few weeks trying to bench bloody 95# like I did.
Unlike Staci, most women stall at relatively low weights due to the lack of genetic talent. The muscle simply won't grow father and strength will not increase to promote further growth. Staci has very LOW BF%, and she always did after she finished her stint with the WW. Her gains were amazingly all muscle. She did not add 10 lbs of fat as soon as she started eating more. And she did add more than average # of muscle mass after dieting since her body is young and talented. We are talking a girl here that DL's more than 2x her body weight. That's a competition level performance not achievable by an Average Jane. An avregae Jane can also expect adding up to 75% of fat to 25% of muscle when gaining weight instead of vice versa, and NO, this fat will not magically disappear! It's the muscule that will once you start cutting....
AGAIN, that's not to say that lifting is a bad thing to do. If it suits a woman, lifting is fun, and challenging. Give it a shot for a month or so, see if the beginner gains are exhilarating, but be prepared to face the reality if it turns out that you are not genetically talented. And if Zumba on Monday and Buts&Guts on Tuesday and Yogalites on Wednesday etc gives you a better sense of well-being, self-respect and a better body - screw the barbell.
There is no magic pill, and that applies to the barbell as well.