L.G.
Everyone loves their own hospital so I don't think you'll get a definite answer here. I have heard great things about both.
I had both my girls at St. Lukes. The nursing staff is very good there. And God forbid you need it, but Texas Childrens is literally a hallway away. I worked in the medical center for several years and am a BIG fan of St. Lukes.
If you are not comfortable with residents, explain your concerns to your physician.