Worse there are a few apparently serious years old bugs.
Ingy is currently rewriting the YAML implementation (in fact, he's backporting the Python port to Perl), which should fix a lot of the bugs. It's my understanding he rewrite is closed to be finished (didn't he get a grand from TPF for this?).
As for JSON being more readable, JSON is actually a subset of YAML - anything that is valid JSON is valid YAML as well (but not the other way around).
If I want Perl to dump a structure which I want to read, I almost always use YAML - I find its output reasonable readable. For input, I prefer ini or apache like config files. I use Config::General to read it. But people vary in what they find readable/writable so don't expect a definite answer in this thread.