2. My previous job was 10 years of mostly proprietary tech. Had no time to pursue other things seriously. Dealing with the newer technologies in a production setting (in the non-profit) helped more than any other learning process would have. Also, going from a small fish in a very big corporate pond to a big fish in a very small pond meant having to take a lot more responsibilities for product, delivery, strategy and HR. It was like a mini skill incubator. I also had enough time to do some serious consulting work, which opened up a lot of opportunities.
3. Quite bad. Savings are quite low currently. My living standard is still somewhat lower than my peers. But opportunities within the next 2-5 years are huge. Had I remained in my old industry, I'd have been a technological fossil by the time I'm 40 (I'm 37 now).
1. Completely upgraded my outdated skill set - from C++/Oracle to ES6/React/Redux/Node.js etc.
2. Completed a life-long dream of writing a full length science fiction novel (not yet published, sadly)
3. Developed computational psychology model (pet interest) that might one day be the basis of a paper
4. Learned proper leadership skills, public speaking skills and people management skills
5. Much better health - exercised, got plenty of leisure time (worked only 30hrs/week)
6. Networked through pro-bono consulting
It was financially punishing for me, but ultimately it was more than worth it. Last year I returned to the industry full time (a different industry this time). The additional skills/experience in the resume opened up a lot more higher level opportunities that I would never have been able to pursue 3 years ago. Right now I'm in a management level position doing exactly the kind of work I want to do, and I doubt if I'll ever have to worry about finding a job...
By the way, for anyone who asks, those 2 years were easily the happiest in my life.
Edit: cons: be ready to be poorer!