Better than I expected. I think A-TEEN has a much higher/mature production value than other series on Playlist, clearly testified by the popularity of the show and its visual treatment. Most actors have done exceptionally good acting. Do Hanna and Kim Hanna are very pretty. Although Yeo Boram's character was far more entertaining, I was left wanting for more of Yeo Boram. Nam Siwoo's story has quite an interesting twist at the end. And I think it would be interesting to see what will happen next in that track.

Theory:
I got this feeling by Episode 23 and 24, that Kim Hanna's character has a lot more depth and complexity than what is shown so far in Season 1. Kim Hanna isn't just trying to copy Do Hanna. She is deeply inspired by her and possibly reveres here. Changing one's name/looks is one thing, but changing schools is a different level of being inspired altogether. In fact, Kim Hanna made effort to be in same school as Do Hanna is. And wants to live with her when she's older. Kim Hanna hasn't shown any interest in any guy whatsoever so far. It is quite possible, Kim Hanna has feelings for Do Hanna and may, in fact, be in love with her. Which explains in some way why Kim Hanna has even adopted Do Hanna's name because she reveres Do Hanna very deeply.