What I like:
1. Musical scoring is ok.
2. Character development were ok, not the best, but ok.
3. Actors can act.
4. It is not like Oxygen. Thank the gods for not including flatness in this series. Though the main actors here seems to just act without trying their best, it is not flat as the main in O2. Also, the series did not include annoying side characters.

What I don't like:
1. Too many pairs. This series has a lot of couples but screen time for each secondary pairs were minimal.
2. No solid arcs for the secondary pairs. They are an afterthought.
3. The ending is just 'meh' for the main couple (Ending for me is EP 12). As for the other partners, since their story were not developed well, the resolution to their arcs were an after thought. And to think that each episode is 40-45 minutes on average is just sad. TH BLs need to re-school their script writing and story telling prowess to take advantage of their longer screen time.
3. The story really starts midway of this entire series. Might be due to the director's or the writer 's decision to tell this story in an alternate universe. But that cause them precious episodes and left them no room to develop arcs for secondary characters.
4. Too many flashbacks.

Now, these are purely my viewing experience watching this series. It might differ greatly from to yours. :)