You can't really rely on APs for a few reasons. First, only about a third or so of high school students take an AP exam, and some of those only take one or two exams. Second, students that take multiple AP exams may take a good number of them senior year, and the scores are not available until after HS graduation (well after they apply to college). And some high schools don't have any or many AP courses.
The SAT and ACT aren't perfect, though they seem to be the easiest way to compare students from different high schools. I also have never fully bought into the HS GPA is a better predictor of college performance than the SAT.
We used to see a lot of SAT scores, along with GPA, for kids when my older two played travel softball. At college showcase tournaments, where teams have brochures with SAT and GPA for each player, there were always parents saying their kid's 4.0 mattered more than their SAT score. I don't think that is true, when my 3.6 kid has a two part SAT score that is higher than the 4.0 kid's three part SAT score (for 2400 SAT of years past). Put both of them in the same rigorous college course and we'll see what happens.
