As has been noted, this formula has been filmed several times, most recently as "You've Got Mail", with Tom Hanks and Meg"Trout Pout" Ryan. Of the several versions, this is my least favorite. The problem i think is that the studio coasted on the Stars charisma, which doesn't quite cut it here.
The chemistry betwixt the two leads never comes to a boil in this movie. There are no real sparks. Van Johnson and Judy Garland remind me of day old donuts, pleasant but bland. And when the leads are boring the rest of the movie can only follow. Judy in particular is disappointing. She looks like she has no neck! I don't know if she was having trouble with pain or something but she looks like a turtle trying to pull it's head into it's shell, all hunched up and everything. I couldn't figure out what Van Johnson was getting so hot about. I would have made a bee line for that cute violin player. And Van wasn't great either. I've always thought of him as a rather generic Hollywood leading man and he doesn't do anything to dispel that image here.
If you're a fan of the stars or the early 1900's then you might like this movie. But there are a lot more entertaining romantic comedies out there, and they offer you much more than a mouthful of stale confection.