I have delivered 2 babies at St. Vincent's and was extremely happy with my experiences. A good friend delivered at Clarian North and was happy, but wasn't nearly as informed upon departure (which may have just been her particular nurses). I had great lactation support at St. V's, however, both LO's were delivered in the middle of the day - I have heard that there is room for improvement during the night. If you are set on St. V's, I think that is a great choice. If not, then I recommend visiting any possible options before choosing a Dr. I went thru the whole process and chose St. V's.
I see Dr. John Cleary with Northside OBGYN. They are located right by the hospital, which is a very nice option because they are able to make it over often to check on you when you are in labor (which is important to me). There are two other great doctors in the practice (one male and one female). I saw Dr. Cleary regularly (I like not being rotated thru a huge practice) and then saw Dr. Myers and Dr. Gaudreau for one appt each so that if they happened to be on call when I went into labor, it would at least be a familiar face.
Before I settled on Dr. Cleary, I made an appt to just meet him, talk, and ask questions to see if he had the same ideas that I had about pregnancy, labor, and birth (I was 3 mos preg at the time). I was very comfortable with him (and both of the other doctors in the practice). It was a great choice for me. I hope this helps you. Best of luck to you!