The wife is a college professor (humanities). My brother is a high school (history) teacher. I'll say the following:
1.) The politics of academia are brutal. I mean, I'm an attorney that frequently gets involved in actual political disputes (abortion funding cases, lobbying disputes, etc.), and I work reasonably often with and against elected politicians and cabinet-level appointees. The politics I encounter are NOTHING compared to what my wife has to deal with. Every decision breaks down to a bunch of diametrically-opposed interests just teeing off on each other. I wouldn't wish it on my worst enemy.
2.) The pay is similar between high school and college. The deal is, there's a wide variation in both fields. In academia, it's often without logic. The public school up the road might be paying $60k starting, compared to the comparable private school at $48k -- or vice versa. It just depends on what funding is available. The way the job market works in academia in most fields is that job applicants really have no leverage and generally take what is offered. I get the impression that there is a lot more predictability in high school -- rural districts make less, urban districts make more, non-unionized states make less, blue states make more.
3.) You work a LOT more in academia. Basically, teaching is probably going to be 15 hours a week when prep time is included. Administrative service is probably going to be another 15 hours a week. Then there's publishing. The wife has reasonable publishing requirements (roughly one legitimate peer-reviewed article a year), and she probably works another 20 hours a week on it. And the whole peer-reviewed thing sucks. If her experience is any guideline, roughly half of what you do is basically tossed in the trash because it is rejected.
4.) That said, it's a lot more flexible. You get off summers, a month over Christmas, a week over spring break, and probably a semester every four years or so. A lot of that is spent researching and writing, but it's still nice to have that flexibility. And every now and then you can take a huge block of time off.
5.) If you make tenure, you're set for life. And it's not that hard to make tenure. (Probably 50-50, and if you actually put in the work, I'd guess closer to 80-20 in your favor.)
6.) According to my brother, public high school kids suck.
7.) But he's having a blast coaching the soccer team. To me, it would almost be worth the pay cut and dealing with high school kids if I could find a nice XC team to coach.
Last, one thing to think about: The success rate on PhDs can't be more than 50% -- meaning only half of the grad students end up getting their terminal degree. And most of those that are there excelled in college. My wife went to an elite grad school with basically a bunch of college valedictorians, and a good 25% of them dropped out. It's not a question of intelligence or capability to do work -- it's just sometimes you get caught without a dissertation advisor to shepherd you through the process, and it's essentially impossible to finish at that point (because you need a faculty member to put your work on his/her colleague's desk and say "READ THIS NOW!"). So you aren't deciding between academia and high school -- it's between grad school (and maybe a 50% chance at academia) and high school.