In Ohio, students have three options: AP coursework with exams for college credit, Early College (classes taught at the high school by high school faculty for which students receive both high school and college credit), and PSEO (Post-Secondary Enrollment Option where students take some courses at a local university while in high school and receive both high school and college credit).
I can only speak for English (which I teach) and math and history (because I work closely with faculty in those disciplines). We have found PSEO students far outperform AP students in our classes, despite the fact that PSEO students are still in high school and AP students are high school graduates. Certainly, the fact that we are an open-admission public university affects these outcomes. It's also important to note that we are looking at a general student population (we have no way of knowing if a student has been identified as gifted, but it's clear to me that most aren't gifted but simply high-achievers.)
When my DD is in high school, I want her in PSEO classes. One reason is the performance difference, but the other reason is related. I think PSEO students perform better because they take courses designed and taught by faculty who are experts in the field not courses designed by a non-profit that acts like a for-profit corporation.
