One client recently told me that when she told people that she had hired a doula (me) her friends envisioned a flower-child, braid-adorned, hippy earth mama. While I LOVE my doula friends who fit that description, that is totally not me. There are also some doulas are who are super strong and assertive and rock 'n roll. I love them, too. But, again, totally not me.
I'm more of an "every-woman" doula... I'm Type A, creative, calm, and loving, yet assertive when needed. (You can read my extended bio here)
Why does it matter?
Your doula needs to be someone you and your partner feel extremely comfortable around. You may feel more empowered when you area around a rockstar doula. You may feel more at peace with a hippy doula. You may feel more in control and well-planned and organized with me, a Type-A "Every Woman" doula.
It's really up to you -- your comfort level with the woman (or man!) you choose to be your doula and how well they can help you feel prepared and knowledgeable and support you -- do remember that they will be supporting you during labor -- emotionally and physically.
I hope that helps make your decision for who to choose as your doula a little easier! There's a lot to be said for personality/persona and you may want a doula who is similar to you or someone completely different. It's your choice. And whatever choice you make will be the right one for you.