As long as you do not take the premise or the characters or the plot too seriously, this is an enjoyable movie with an interesting pairing of Fred Astaire and Audrey Hepburn, plus an excellent supporting performance by Kay Thompson and some good-looking settings and scenery. The musical numbers are pleasant, if rather on the light side. Stanley Donen has the right touch in keeping things together without making the seams show too often.
Hepburn is cast in a somewhat unexpected role, as a drab intellectual store clerk who gets involved with Fred Astaire's (much older) photographer character. Audrey is so charming that's it's very difficult to think of her as a wallflower, and while Astaire is as energetic as ever, there are more than a couple of occasions on which the relationship doesn't really look believable, despite the best efforts of the two stars. The plot isn't supposed to be anything weighty anyway, so perhaps that's the price you have to pay for a rather different pairing.
Kay Thompson provides many of the best moments. Sometimes the satire of trendy philosophy comes off well, at other times it gets a little dull. Not to be forgotten are the colorful and interesting settings and backgrounds, which set off the story and music fairly well. It's sometimes a strange combination, but as lighter entertainment it all works well enough.