I've heard of many people using Andrea's course and getting good results. It's even featured in Transamerica where the main character uses it to learn how to speak. For me, I tried it and it was frustrating as I was going nowhere with it. Making all of those eeee-uuuuurrrrr sounds over and over didn't make sense to me and watching Andrea do it was kind of funny and frustrating at the same time because I kept failing at it and she was doing it so well. I've also tried Kathy Perez's 3 CD course, too. Certainly, I can speak in a feminine manner, but to have someone consistently hear my voice as a woman's voice? Uh uh, don't think so. I just sound like a man trying to sound like a woman. And no disrespect to Perez and her wonderful work, but I'm not really a fan of the transwoman's voice on her CDs. Andrea's voice, however, is very good. It's got that quirky quality about it and it's totally believable.
As I've said before, I've let my appearance totally dominate and be my strength for many years, so much so that my voice is seen as a distant secondary thing (the pretty girl with the man's voice syndrome). That's why surgery will help me. I'll get that desired pitch without even thinking about it. I've got the resonance and the prosody parts down, but I definitely need a pitch change. Your mileage will vary on using any voice changing method, so the best thing to do is to buy any or all of the options available to you and try them out one by one and see which method works best for you. Maybe one of them will work great for you or maybe you'll end up concluding what I've concluded.