Teaching hospital OB or private practice OB?

I'm facing a delima right now. Need some advises. I moved to a new area and need find an new OB as soon as possible. 
One is associate with a big teaching hospital,  occupied by attending physicians and few student. Delivery will be down by attending and with student's help. Have high risk experiences. ( I'm not a high risk patient)  
Offer sonogram at 12 weeks and 20 weeks
The other one is a private practice, one older doctor and two very young doctors and two midwives. Delivery will be down by doctors or midwives, depending on thier schedule. No student involved. Can not handle high risk patients. Offer sonogram only at 20 weeks. 
Both OB office use same hospital for delivery .  
I don't know which one to choose.😖😖😖