Just another parent perspective here – at our urban magnet school, the IB program was the elite/most rigorous program offered. Students who took AP or were not Diploma candidates did not get the “most rigorous curriculum available” check on their guidance counselor form that went with their college applications unless the reason they were not full IB was because they were taking upper level math etc. at a nearby major university. So, I would encourage families choosing between IB and AP to understand their school’s policy on the GC form – do non IB students get that “most rigorous” designation? If not, a student aiming for top 20 (and perhaps top 30+) schools will likely not be given serious consideration because admitted students will have taken the most rigorous high school curriculum offered by their school.
Next, find out more how CAS works at your school before concluding it would require “add ons.” My kid was an extremely busy athlete and musician, and his school and outside-of-school involvement in each of those counted for “activity” and “creativity” hours. He had to write some reflections, but otherwise, there was no extra time spent on anything. The service component of CAS was the same as what he had to do for National Honor Society, so again, did not require extra commitment.
Finally, think about educational goals. IB is reading and writing intensive so that students develop the critical reading, writing and thinking skills that are necessary for college success. TOK is an unusual class for high school students, many of my kid’s friends loved that it because it was so different from their previous high school experience of “teaching to the test.” Please see added comment at the end of this post, to incorporate comments made by other, wise posters – The usual critique of iB is that it requires STEM kids to take more, and more rigorous, humanities type classes than they would otherwise want – since most students take HL English and HL History – both of which involve lots of reading and papers. So, for a student who, for instance, is only looking at engineering, IB could limit the course selection in high school.
Bottom line – find out more about what IB means at your school since there is a lot of variation in the US in how various IB curricular requirements are implemented. Talk to parents of rising seniors and current college students to understand more about their experience. I will say, my IB student found that college classes were not a shock, he felt well-prepared and able to manage the demands of being a college athlete and student because he’d been doing that kind of time management for his 11th and 12th grade years. There is no “right” answer here, just the better choice for your student!
Edited to add – as @skieurope and @ucbalumnus noted below about HL classes, find out more about specific courses offered at your school, to see how the offerings meet your student’s interests and goals. My own kid’s school had limited STEM HL offerings, so that was the criticism of the diploma for STEM kids, that they had to take HL English and History to meet the HL requirements. Other schools may do a better job at offering a diversity of HL offerings.