As someone who took 11 AP courses in high school and received 5/5 on each for ~35hrs of college credit at Texas A&M University, a nationally respected engineering college, I feel I can speak authoritatively on the benefits this has for students.

Before proceeding, here is the list of tests I took:

Sophomore Year: Geography

Jr Year: Calculus BC, Micro & Macro Economics, Government, English Language

Sr Year: Computer Science AB, Physics C, Statistics, English Literature

I also had amazing teachers, many award winning including a NASA scientist and a former Defense Department programmer.

First, most of the best colleges limit the scores they are willing to accept in exchange for credit. When I attended college, 5s were required in major specific studies in order to receive credit at Texas A&M, which if I recall correctly was how it was at MIT, the Naval Academy and various others. A 5 on an AP exam in my opinion is par for a passing grade in a college course. When I started at Texas A&M as a Mathematic/CS dual major, I started in Calculus 3 and CS 211 (~3rd semester equivalent). Material-wise I was more than capable of handling the classes, and even found that my background had been far more rigorous than many of the other students.

The only problem AP courses caused for me were an issue of my advisor who allowed me to take 15 hrs of sophomore level courses my first semester as a Freshman including: Discrete Math, Cal 3, CS 211, Statistics 211 and Biology 101. In retrospect, this was a huge mistake. Emotionally, I was not prepared to handle the course-load and struggled. This was exacerbated by the fact that it had actually been a year since I'd taken any Calculus since I took the AP Cal BC exam my Jr year. I would have been much better off with the minimum course-load (12 hrs) and a few lighter classes. Unfortunately, due to my entire semester's worth of earned credits and a dual major, I had little to no "lighter" courses left to take in my degree plan.

All in all, to hear someone claiming AP exams are a "scam" is absurd and laughable to me. They saved me roughly $20,000 in in-state tuition & board at a public university! I expect the savings to someone attending a private university would be far more profound (on the order of $100k). If anything, the biggest problem with the AP system is that schools do not sufficiently equip students to either take the exams or made sufficiently aware of the benefit they offer.