Put aside any preconceptions about "Mickey and Judy" movies. In fact, put aside the film entirely. It's watchable, but who cares? The reason to see this film is for the fantastic arrangements of some of Gershwin's best songs.
Hugh Martin and Ralph Blaine, soon to be famous for their score for "Meet Me in St. Louis," gave the Gershwins' score (their best show), the five-star treatment with fantastic vocal arrangements - though I'm sure Roger Edens also had a hand in there.
What you get are versions that make these great songs sound even better. "Bidin' My Time," which can be a sleeper if done badly, turns into a rich counterpoint between Judy and a male quartet. "Embraceable You" is given an easy, lightly swinging full choral arrangement after Judy has her turn, and "I Got Rhythm" is taken over the top with Tommy Dorsey and the "Six Hits and A Miss" backing Judy perfectly.
But the piece de resistance is Dorsey's arrangement of "Fascinatin' Rhythm," presented first as a typical swing arrangement (and a great one at that), and then with Mickey playing (appearing to play, actually), a piano solo a la Gershwin's "Variations on I Got Rhythm," complete with hand-crossing and all George's piano tricks - fantastic! Add to this Judy's painfully tender version of "But Not For Me," June Allyson's debut performance of "Treat Me Rough," and you have one of the best film scores ever. ("Bronco Busters," unfortunately cut from the film, is available on CD - in stereo, as are all the tracks.)
If you are a Gershwin fan, this film is a treasure. Thank god they didn't throw out the best songs, as was done a few years earlier when Rodgers & Hart's equally impressive score for "Babes In Arms" was butchered for that film. I guess you had to be dead before your work was treated with respect in Hollywood!