"Women" and "females" are both fine for me. The worst thing is when men are referred to as "men", and women are referred to as "girls" in the same discussion. No.

"Girls" is only ok when referring to children, or in very casual use to refer to a group of female friends. i.e. "Hey, going out with the girls tonight?", or if the male pronoun in that situation would be "boys" or "guys".

If a discussion is going on about gender, as long as no one uses "girls", I don't like when someone brings up "Hey, you should use the term "women" instead of "females"" (or vice versa). It reads as just another way to get the discussion off-track from the important issues.