Thanks mominsac for kind words.
By judging the two schools in our school district which offers IB and AP with metrics like average SAT score, number of NMS semi-finalists, number of kids go on to UC Berkeley, the number of kids go on to Ives + Stanford + MIT, the two programs are pretty evenly matched. You can find successful stories to back up either side. Admitted that it is very small sample pool but I did not see any evidence to support that IB is far superior than AP.
The discrepancy of NMS semi-finalists that you saw in your school district's two schools is probably due to student self-selection. More often than not is that good students make good schools rather than the other way around.
