I've experienced some bad paid dependencies forced on us by a non-engineering team. I've had a few good experiences with "open core" kinds of dependencies that are widely used by the community, e.g. sidekiq, and therefore less likely to suddenly vanish one day as they would almost certainly get forked and maintained by others in the same boat.

The upside of paying for something is that, assuming the owner or company is stable, I don't have to worry about some unpaid solo maintainer burning out and never logging back in.