I've never bothered to learn much AWK, but that's mostly because Perl is my bread and butter language and has been for 20 years, and focusing on knowledge of that seemed a better investment (especially since with a few judicious flags, Perl is a passable AWK replacement even for very small one liners).

That said, if you just want to supplement your knowledge of other shell tools and pull out something that can do some obvious text munging, AWK has always looked attractive for the task to me.