If you want a natural birth, then the important thing is to find a doctor who is pro natural births. Mine is and he's located in Montesur. If this is what you want, then you must make your wishes clear from the very beginning. If it doesn't matter to you, then chances are you'll probably end up with a c-section. I've known about 20 women to give birth in the last 1.5 years. All but 3 have been c-sections. 14 were in Montesur and were c-sections, 1 there was natural, 1 was in Santa Isabel (natural, but the mother was pushy about this), 1 was in Clinica Americana (natural), and I can't remember where the other one was...but it was also natural.
The best clinic is Montesur both for the mother and the baby. Ask any doctor located in any clinic and they will tell you this. Other clinics are great too, but if you want the best, it's Montesur.