Hi M.,
I'm fairly biased towards a doula, especially since I am a certified doula through DONA and a childbirth educator. :) Statistically, here are the numbers for women who choose a doula:
~ Cesarean section rate is reduced by 50%.
~ Length of labor is reduced by 25% (an average of 2 hours shorter).
~ Pitocin use is reduced by 40%.
~ Use of forceps in delivery is reduced by 40%.
~ Epidural requests are reduced by 60%.
~ Use of other narcotics for pain relief is reduced by 30%.
A doula offers continuous labor support from the time you call her in labor until after the birth, something that L/D nurses simply cannot offer becuase of staffing issues. Even if you have a completely supportive coach/husband/partner, a doula can be an advocate for you and a source of comfort just in her presence. I've attended some births where the husband was the perfect coach and I felt that I was not needed, but afterwards he was the one that said just being there "in case" gave them great confidence. A doula will do whatever is needed, whether that be to offer emotional and/or physical support and comfort, or offer information in case different situations come up.
Be sure to choose your doula carefully! Since birth is such a personal and amazing experience, it's important to find someone compatible with your personality. Thankfully, we have lots of wonderful options in our area.
I wish you the best and congratulations on your previous VBAC.