I mean, all of the females are impressive. I do like Hawkeye and Izumi, but once Olivier came into the plot, I was blown away. She's basically GAR (I know this term is used only for manly men, but come on... she's super bad@$%).
Winry ~ and Mei ~ Though I love badass-y characters in general like Riza, Armstrong, LanFan, or Izumi, I feel that having a strong, developed female character such as Winry in a shounen manga is so much more refreshing than just your typical badass. Winry is badass in her own way, and is very feminine as well - which I like. :3 And how could you not love Mei?! <3
Lust was...eh...she didn't have much screentime, I don't think. I think I would have appreciated her more if she had more screentime.
There's no possible way to dislike a female character in this. Honestly. All of the characters are just THAT likable. ^_^