In my personal rating system of "loved," "liked," "meh", and "nah", this rates a "liked"/"meh".

What I liked:
I, of course, liked Vin Zhang, but then again, I could probably watch a drama that is just him watching paint dry and I'd be okay, as long as I occasionally got that quirky slightly crooked smile of his. I also like that he is not afraid to play opposite female leads who are older than him (like in "I will never let you go"). I thought both FL and ML actors did their roles well. I appreciated getting to hear their normal voices and neither one bothers me. Of course, I also do not speak Mandarin, so there's that. I liked their opposite natures: ML was cheerful and often irreverent, FL was by-the-book and serious. Their romance was believable (and there was even a kissing scene. If I was Yang Mi, I would have made VZ do that take at least ten times. You know, for science), but I did get a bit frustrated by the FL's unwillingness to let anyone into her life. I loved ML's family. They were hilarious and had a good relationship with their son (and for once, the dad was played by an actor who was handsome enough in his own right to have believably produced a son who looks like Vin Zhang.). Despite the initial drag of the plot, I actually got into it as it moved along.

What merited the "meh" portion:
I'm not really into procedural police dramas and this was definitely procedural. Lots of time spent in conversations about the case and what they were going to do. Thanks to censorship, plenty of patriotic script writing--I had to fast-forward through those bits. And I know this is most likely due to censorship, but I had a very hard time believing in a government agency that had zero infighting, zero bosses under political pressure, zero problems interacting with local police forces, and zero territorial disputes with other agency offices. In a way, that is what ruined the other very realistic-seeming parts of the drama.

If you're really into procedural law & order-type shows, you'd like this one, just be aware of the limitations due to censorship outlined above. I thought all the actors did a nice job and I did not feel I'd wasted my time watching it.