The key thing to note here is that there is lots of INTRA-career variability both at the high school level and the college level. A job teaching at a small liberal arts college that does not emphasize research is going to be very different than a job teaching at a large research university. Similarly, a job teaching high school at a public school in a depressed Appalachian community will be wildly different than a job teaching at an elite prep school.
A few things to consider:
1. Salary. A good public school district will pay a bit more than a small, non-elite level college. A prestigious, large university will pay more than either. At the college level, pay is also very dependent on the subject you teach. E.g., business faculty typically get paid far more than humanities faculty.
2. Lifestyle. The work of a high school teacher will generally be less flexible, but not necessarily lower in volume, than that of a college professor. As a high school teacher, most of your daily schedule from 7:30am-3pm or so will be dictated to you. As a college professor, you'll be in the classroom anywhere from as little as 3-6 hours per week (at some large research universities) to 15 hours per week at a community college. Beyond that, most of your time is your own (note: you will be working much more than 3-15 hours per week, it's just that the additional hours can be spent when, and possibly where, you want them to be).
High school teachers spend the vast majority of their time teaching, grading, and preparing for classes.
College professors' duties are more varied. You'll have the teaching that I mentioned above. You'll also have research responsibilities. These are generally inversely proportional to the teaching load. If you're teaching only 1 class a semester at a large research university, you better be publishing multiple times per year in top tier journals and also bringing in grant money, if you want a shot at tenure. On the other hand, if you're at a low key small school teaching 4 classes per semester, you're probably fine with 1 reputable publication per year or so, which shouldn't require tons of time. You'll also have some service responsibilities to the university (serving on committees, etc). The requirements will vary quite a bit from place to place. They are generally not terribly time consuming, unless you want to eventually work your way up to some kind of leadership role in the university. You'll also need to schedule time for things like office hours and advising students.