I thought this show was just ok. It started out promising, but kind of petered out toward the end. I thought that the ending was confusing (regarding the time travel element) and was sort of a cop out. I did like main characters - Hyun Jae, Woo Seung, but the whole storyline was too meandering to really have a solid plot and they focused so much on the main OTP that the other characters really suffered from a lack of development. Ji Hoon, Hye Ri, Drill, and the others were all given a good intro, but there was no follow through on delivering any sort of storytelling for their characters.
The show wasn't a total waste of time and there were cute moments and decent music, but overall I would not watch again.