Huge boost for my mental health - I can go for beautiful walks anytime I want, the local village has a huge sense of community, I've been spending more time with my family (which I'd neglected while building my career abroad over the last 15 years), the food is so tasty and all local, I'm very close (~30 min drive) to mid sized cities, and my cost of living necessities is not even 1k euro a month...
The one downside is that dating is pretty close to impossible. Pretty much anyone over the age of 25 has kids, and it's not in tiny mountain villages that you'll find people who are into the same kind of nerdy multicultural things that you are. (the postwoman is pretty cute but huh that seems like a bad idea). I've been back in the bay area for work since, but turns out "I spend most of my time on a farm in rural Europe" is a turnoff for city people, YMMV.
So definitely do it after you're partnered, if that matters to you.