From and IMDb user comment:
...But what really makes this one special are the performances of Grant and Hepburn. Grant is as charming as ever, but just a bit looser and slightly less debonair than he is in most of his later roles. And it becomes him; he endows Johnny with youthful exuberance, good looks and personality, as well as a carefree yet responsible attitude that makes him someone you can't help but like. And Hepburn fairly sparkles as Linda, a role she was born to play; this young woman filled with a zest for life and an indomitable spirit. She imbues Linda with that same, trademark Hepburn feistiness you'll find in so many of her characters in films like `The Philadelphia Story,' `Adam's Rib' and `The African Queen.' All of whom she plays with a variation that makes each of them unique. And it's that personal spark of life that she's able to transfer to her characters that makes Hepburn so special. Whether she's locking horns with Tracy, pouring Bogart's gin into the river or falling in live with Grant, nobody does it quite like Kate. And Cukor had an affinity for Hepburn that enabled him to bring out the best in her, always. Arguably, her best work was with Cukor.
The memorable supporting cast includes Lew Ayres (Ned), Edward Everett Horton (Nick), Binnie Barnes (Laura), Jean Dixon (Susan) and Mitchell Harris (Jennings). A thoroughly enjoyable film, `Holiday' makes a subtle statement about embracing the time you have and grabbing for the brass ring while you're still able; that in the end, life is what you make of it. But Cukor never lets it get too serious, and never lets you forget that the main thing here is to have some fun, beginning with this movie. And by the time it's over, the world seems just a little bit brighter somehow. And that's the magic of the movies. I rate this one 8/10.