But this is a great post that covers the relative behaviors of the different parsing libraries and helps you evaluate the best _functional_ choice for your needs. Bravo!
One issue I've run into is programs that have configuration language that looks a lot like TOML or INI format... yet it's neither. So a TOML or INI parser might be able to read and write the configuration files 90% or the time, but fail in strange ways in some edge cases.
What I never understood are those who looked at all these options and said "No, I'll write my own parser!" instead...