I studied math at MSU and work with math students at OTC. For calculus, you'll get pretty much exactly the same curriculum at either college. Sometimes it's even the same teachers. It's maybe better at OTC in some cases, because most of the teachers are just there to teach, whereas MSU professors are also doing research and publishing and so may treat teaching as a secondary responsibility. In my experience, at OTC, it will be easier to get personalized assistance like free online tutoring over the weekends or scheduling accommodations. MSU has more of an academic culture though, like students working together collaboratively outside of class hours and challenging each other with interesting ideas and projects. For physics, chemistry, and computer science, it's my experience that MSU has more challenging curriculum and more capable professors. Your future instructors at S&T probably have experience with students from both schools too, and it wouldn't be a bad idea to call them up and ask them directly for their opinions.