Personal opinion is going to vary on this becuase there are many different types of classes and different levels of personal investment into the class.
If you're a person who's just going to be a chair warmer...it may not help you much becuase you're not helping yourself.
If you are going to be serious, practice the techniques, and do your part, then you'll notice a difference.
The studies are clear. Those who take classes have better outcomes and experiences than those who don't IN GENERAL. That is even MORE true if the classes are other than the standard hospital class BECAUSE, as one person stated, those classes aren't so much designed to help you work with your body and teach you comfort techniques but rather to explain to you the procedures and practices of the facility...they tell you what to expect as an average patient. AND often times, the standard hospital class mocks the unmedicated mother in labor. I personally find that unethical and ridiculous.
Each birth is different. Whether you're having your second, fifth, or eleventh baby; it will be a different experience as your baby is a different child than who you've birthed before. The staff will be different, the room may be different, the time of day, the onset of labor, your age, your fears, your relationship to baby's father, your overall health, your mental/emotional state, your life stresses, your homelife, those you choose to include into your personal birth team ALL affect the flow and process of birth. So...it's always worth a refreshed look at the information. Not to mention the new things we're learning daily about health and childbirth.
I would highly suggest looking outside the hospital for classes to teach you coping and comfort techniques, nutrition information, and empowerment exercises. Do your research. There are many different methods:
**Birthing From Within ( www.birthingfromwithin.com ),
**Bradley Husband Coached Birthing ( www.bradleybirth.com ),
**Hypnobirth ( www.hypnobirthing.com ),
**Hypnobabies ( www.hypnobabies.com ),
**Lamaze--which isn't a "method" anymore as much as a philosophy--( www.lamaze.org ),
**Eclectic classes taught by birth professionals around the country taking from their experience, knowledge, and training to share what has worked best for the women in their practices and cliental.
All of these have proven to be significantly beneficial to women and their partners. Coming second only to having a Doula, which, agian, I HIGHLY recommend. I, myself, would sooner jump off a cliff and slit my throat than give birth without a doula regardless to whether I was choosing an epidural birth or a completely unmedicated home birth...I just would NOT do it--EVER. I'd do research on that, too!!
I hope that helps...and CONGRATULATIONS!!