There are POSIX compatible regexes which are used by tools such as awk,sed etc and the rest are Perl compatible regexes.
So Perl has set the standard and any other language has Perl regex compatibility.The other thing is that Perl evolves the standard with new additions (such as named captures ,posessive quantifiers etc) and optimizations and the others follow.
So it is still a key point of using Perl and I would certainly choose Perl for its regex support.