Question for Anyone Who Has Used a Doula

So I just got back from my midwife appointment and it left me feeling a little bit concerned/stressed/unsure.  The office I go to is pretty awesome.  The have two OB's who basically work with clients who choose doctor-only care, and act as backups to the midwives.  A doctor is "in-house" for each birth, but only attends if the midwife requests.  There are four midwives who work on a rotating on-call basis, so we will be having at least one appointment with each.  Another cool part of this office is that they also have four Doulas on staff.  For a low fee ($300...typically a doula will range from $500-$1500 in this location), you can sign up to have a doula present.

Since I am going to try for a natural birth, I signed up, since I know having a doula can make a huge difference in terms of providing labor support and coaching through pain.  Here is the part that makes me nervous...typically, if you were to hire a private doula, you meet with them once or twice prior to birth, go over your birth plan, your hopes, your fears, and establish a rapport.  Then the attend our birth (sometimes first seeing you at home) and usually see you at least once after birth to check on you and make sure bonding/breastfeeding/recovery is going ok.  Well, I asked about it today at the office and apparently they have a weekly "open house" where you basically go with a group of other parents and meet all of the doulas all together and they talk to you about the experience and what to expect.  That's it.  One of the doulas isn't even there because she only works one day of the week.  So...no meeting, no real rapport establishing, no going over your individual birth plan or fears, no coming to your house.  So basically, once you are at the hospital or  birth center, one of the four doulas will show up, and leave after delivery.  You may or may not have even meet them beforehand (if it's a Friday). 

I'm just not sure this is really even worth it.  While it is cheaper, what if I don't like them? What if they aren't supportive of my choices? What if they're just kind of a bitch?  I worry not only that I would be lacking the support I want, but that I wouldn't be able to ask them to leave (comfortably) since they work the midwives that will be delivering.  I just don't want to have any additional potential for stress in that moment, since I'll already be well into labor when I first meet them. 

Also, I can't really imagine sitting down and going over my birth plan with this person in-between contractions....granted, they'll probably have access to "my file" and all, but that's not really the same.

I just don't know...anyone who's used a doula in the past...what's your take on this? Was the rapport/relationship you had with your doula, even just a baseline one, something you felt was really important in the experience?

Any help is greatly appreciated!

Edited: Spelling