Substitute teaching is going really well, much better than I expected. Basically, you're teaching but not having to prep or assess, i.e., grade, which are the two biggest time-sucks in education.
Am I a great big target for student harassment? Yes! But as long as the teacher has left behind a reasonably coherent lesson plan I feel confident and have thick enough skin to make it through.
I've worked with a severely autistic kid for entire days. One day I was basically a glorified study hall monitor. At the end of last week I taught biology. In one week I got two different offers to go "long term" with the schools -- this would mean a slight pay-bump, and honestly I think it's a trap. If you really like the position, that's great. But that's not nearly enough pay to get back into lesson planning and grading.
The variety is great. Not forming relationships with students is a downside but honestly not something I'm too worried about. Right now, it's a paycheck among other things and not a bad one. I finish the day somewhere between two and four p.m. and take nothing home.