PHP requires escaping quotes and literal backslashes (i.e., backslashes not used for metacharacters or escaping other characters). For many cases, it doesn't affect anything, but it can turn into a bit of a nightmare if you're matching anything involving backslashes since you need four backslashes to match one literal backslash. Perl's regular expression literals are also nicer for things like splitting a long expression over multiple lines.

I thought preg_quote() took care of that just like quotemeta in Perl?