I like small instances too, they feel more like a community. Unfortunately, most of the ones I've been on have shut down.
Now I try to look for an instance that takes donations. To me that means they take their job seriously, and they're not just doing it as a hobby or for learning experience.
For Lemmy, Mastodon, etc it probably doesn't matter, your messages will still be available if your instance disappears overnight. But with Peertube, try to go with a big, well established instance. Right now I have to re-post my videos to a new instance since libre.video kicked the bucket last year.