This is an easily digestible, fun, gorgeously shot, and more-intelligent-than-it-should-be kind of musical. It is the perfect movie to put you in a good mood. This helps with Hepburn's charm, Astaire's presence, and Kay Thompson's sardonic wit. However, when Astaire and Hepburn first meet, Astaire randomly kisses her without any warnings, which my girlfriend noted, "That's sexual harassment!" and I do agree with this site's review that there is a very old fashioned view of gender roles in this film.
PS- Not to be a Negative Nancy, but there's something kind of "white suburban parent pipedream" about this website's review; just the thought that one will discuss Sartre and Derrida with your 9-year-old kid strikes me as delusionally high-brow. I imagine after watching this movie you had your kids read through The Second Sex and write a dissertation about gender performativity...