INI is great until you need to store anything with more than minimal structure. Lists and tables can be hacked in, but are not really supported.

I've had to write code like this:

my $param = get_ini_param('Foo','Bar');
my @param1_params = split /,/, $param;

# repeat for 37 different parameters with different parsing requiremen
+ts, slightly different structure.
[download]

too many times. In the end I wind up rolling my own text serialization library just to use INI format.

YAML solves this problem very nicely and, IME, it is easy to edit by hand.