I went with a Family Practice doc for my care during both my pregnancies.
During my quest to get pregnant, I met two wonderful OB/Gyn's. One did 30+ deliveries per month during his on-call week and the other did 10-15 during her on-call week. Only in rare cases did either deliver their own patients (unless you happened to go into labor when they were on-call). Both OB clinics also required their patients to meet each Dr in the practice at least once during their pregnancy. So, especially in the case of the one clinic, I would have had a different doc just about every visit of my pregnancy. In an effort to help calm my first-time mom anxieties, it was important to develop a relationship with my Dr. I chose the family practice route.
I went to the HealthEast Vadnais Hts clinic and chose the same Dr I had been seeing for my annual exams and sick visits, for my prenatal care. She also delivered my babies, rounded at the hospital after my deliveries and is currently both DDs doctor. On average, she does 6-8 deliveries a month, can handle any delivery (including VBACs) except for c-sections and partners with two OB groups for c-sections and pregnancies with multiples. I know her and her clinic nurse and trust that when she's reached the limit(s) of her experience and knowledge (which has happened a couple times), she'll refer me to a specialist. The HealthEast care system really encourages the family practice model of care.
Ultimately, I think it's a personal decision based on your personality, the personality of your Dr, as well as, your comfort level. If you'd like to see one Dr for everything, including your pregnancy and well-child visits, I strongly encourage you to look into a family practice doctor.