My school offers AB, and the teacher is very good (I had her for geometry). We don’t have BC, but our school participates in an online program through which I could take it. Schools often offer more credit for it, plus I just like math, which is why I’m considering it. There’s only one person in my school who’s taken BC online and he says it was fine (he got a 5). I’ve used this online program before for Algebra 2, and the teacher wasn’t very … present. It took him about four days to get back to you. If I needed help in BC I’d probably be able to go to my school’s AB teacher. I did very well in H precalc (A+) so that won’t be /too/ much of a problem, but I’m also taking four other APs next year so I’m wondering about workload differences between the two classes. Suggestions?
What ECs are you doing? (e.g., how busy will you be)
What major are you interested in?
Seems to me that Calc AB would be fine.
I’ll also be in AP Chem, AP Physics 1, AP Economics (for both tests), AP English Lit, and honors Spanish 4. I’m going to cut some of my extracurriculars but I’ll still be in math league and a robotics competition that eats up a lot of time. I plan on majoring in physics or material science.
I would take BC. I guess it depends on your school, but my honors precalc class junior year was basically calc AB without the AP exam. If you are a strong math student and want to major in physics, I suggest BC. It is not overwhelming with other AP classes, at least in my opinion, and I also took four this year (AP chem, AP lit, AP comp sci, and BC). I also was very busy with work, sports, and clubs and still found it manageable.
Also, basically all of calc AB is in the BC curriculum, so the AB teacher should definitely be able to help you if you struggle. If not, two great websites include skylit and mr calculus. They show you AP problems and walk you through the correct answers/approaches.
This is a bit of an anecdote, but I had a lot of friends who were placed into BC but took AB instead. They now find the work too easy and wish they chose BC. Take that with a grain of salt though; you seem like a smart student who will make the right choice for yourself. Good luck! 
TBH, whichever decision you make is fine.
If the school offers any credit for AP’s, BC will pretty much always get more credit than AB.
Just based on those statements, I’d say choose BC because you may find the pace of AB too slow. Yes, it will be a bit more work, but you’ve more than likely been exposed to at least some of the AB topics in H precalc, so you should be fine. If you get stuck, the AB teacher at your HS should be able to assist.
But like I said initially, you really can’t go wrong either way.