To put is simply, priority enrollment is GOLD. You control your schedule with the most flexibility, take the best teachers, and attain HIGH GPA. Students with 120+ completed units can’t enroll in classes, because they fill up prior to their enrollment window. CHP doesn’t have that problem. Many accepted CHP, start at CHP, get the priority for a couple of years, then drop the CHP and use AP credit for certain classes they would not be able to do under CHP and free more time for research or for studying and graduate with latin honors. Search the UCI Reddit, plenty of strategies there.