We hired a doula for all three of our births (the same doula). Even with my background in healthcare and EMS, I was well, not useless, but also not as useful as one might have liked.... She did great in helping us. In a lot of ways, while I was supporting my wife, she was supporting us both. She coached us through a lot of different ideas and suggestions for helping labor to progress, and she was worth every penny that we paid.
She's also recently become a nurse midwife.