We visited L'atelier in the evening, and the exhibition was mostly empty save for a few other guests - it was like we had the whole place to ourselves!
The exhibition was simply amazing! The sets were done up beautifully, with allowing us to feel as though we were in the various paintings and scenes.
The three shows are a must watch, they literally bring the art to life! We caught the last shows of the day, and the staff were simply amazing. They gave their best efforts to the show (and went beyond to interact with us), even though we were the only two in the audience.
While the shows and exhibition was in Korean, there is an app you can download on the spot (there's free WiFi at the exhibition) for you to listen to in English (and other languages, I presume). It even syncs with the timing of the dialogue in shows!
This exhibition is underrated, and I can't recommend it enough.