Annecdata: as a teacher in an inner city high school, I did not break past 50k/year for the three years I was there. That includes the summers I worked. Between grading, lesson planning, meetings, and teaching, my typical week day started before 7am, ended around 8pm or later. Typically most of my Saturday was used up and half my Sunday. Normally all of spring and winter break was used up likewise. I typically got close to a week off in summer.
As a developer, I started at nearly 2x what I made as a teacher. After getting real experience, I make more than most administrators and more than any teacher could after a lifetime of service. I have multiple weeks of paid vacation. Aside from a (weak) pension, my benefits are better. My work only follows me home when I am behind schedule (not often) or when there is an outage (a bit cyclical). My quality of life is so vastly better. Another benefit, I now get to work with motivated and smart individuals.
It's my understanding, from an ex-gf in college who was going through the teaching credential program at the time and had a mother that was a teacher, that there's a lot of work loaded on teachers inthe beginning, as they need to develop lesson plans for everything from scratch (where "develop" may mean find and adapt in some cases). Then, after a couple years it's settles into a normal churn of updating or replacing a much smaller portion of lesson plans as you go, and the rest of the time is the normal grading work.
That said, I'm not sure I've ever met a teacher who takes off at 3:20 every day. I imagine it probably averages out to around an hour before and after school, so 7 AM to 4 PM? But there's often grading that happens at home throughout the week. I wouldn't be surprised to see veteran teachers averaging 44-50 hours a week of actual work for the year (with lulls and spikes for midterms/finalls, etc).
Teachers make less to start as a result of the unions. The people running the union are later in their careers so the increased wages tend to accumulate to more senior positions. At least, that's how it's going for my friend who is a teacher.
Once you put in the time it pretty much turns into one of the most comfortable jobs you can get between decent compensation, lots of time off, good benefits.
As a developer, I started at nearly 2x what I made as a teacher. After getting real experience, I make more than most administrators and more than any teacher could after a lifetime of service. I have multiple weeks of paid vacation. Aside from a (weak) pension, my benefits are better. My work only follows me home when I am behind schedule (not often) or when there is an outage (a bit cyclical). My quality of life is so vastly better. Another benefit, I now get to work with motivated and smart individuals.