Popularity of a non-overnight type is one of the biggest reasons to use something like Postgres or Rails: this means it gets beat on a lot, there is documentation and you can find people who know how to use it.
Some projects with this kind of popularity (n.b.: not the ones I mentioned by name) are designed like shit, do irrational things, have performance problems, have security problems, whatever. But they have been used and they are usable and you can find documentation and experts to deal with them.
Some projects with this kind of popularity (n.b.: not the ones I mentioned by name) are designed like shit, do irrational things, have performance problems, have security problems, whatever. But they have been used and they are usable and you can find documentation and experts to deal with them.