This show is divisive. It's got avid fans or serious detractors. I enjoyed this show, but acknowledge it had major flaws.

Firstly, I have not read the novel, but am aware of deviations from the original book. If a true drama adaptation is what you're looking for, you'll be disappointed.

The plot premise is young lovers torn apart due to class differences, with the FL's family (in particular her mother), disapproving of the ML. 10 years later after many trials and tribulations, the couple reunites, as adults. It's a journey of them uncovering their passion for their work (particularly the FL as a doctor), rediscovering their love, and garnering the bravery to stand up for their beliefs and find their way back to each other. The ML is a noteworthy and honourable firefighter, and the FL, a cold, yet talented doctor.

Flow/ Love line.
The Song Yan (SY) and Xu Qin (XQ) love line is drawn out and they don't get back together until after ep 25. XQ is highly weak, indecisive, and bounces back and forth between wanting to get back with SY. Her personality is a result of decades of being suppressed by perfectionist, disapproving parents, leaving her as a seemingly lifeless pushover. The plot didn't pick up until the earthquake story from ep 23-24 onwards. You get 5-6 episodes of sweet, overcompensating skinship, passion, and chemistry, and then the plot resumes to XQ uncovering her family's sabotage of SY in the last decade.

I also am with fans who agree that the mother did not get the karma/justice/poetic justice she deserved.

While 40 eps is not extremely long for a Chinese drama, a lot of the first half were filler, and besides the firefighting scenes, there was no real substance or progress with the love line. Acknowledging that even for some of my favourite shows such as Love Like The Galaxy, I found the plot (eg first 14-20 eps of that show), didn't have much progress with the love line either. Leads usually get together in the second half.

Acting
Yang Yang is another divisive actor. People either love him or hate him. I am a fan of him, but acknowledge that he isn't the most expressive actor.
If anything, the weakness in this show for me was Wang Chu Ran. She's pretty and has an elegance about her, playing a 29-30+ year old when she's actually 23-24 (whereas other actresses her age such as Zhao Lu Si are playing youthful, high school students for example), I did find her performance lacking. XQ is a cold, scared character, but I felt WCR's inexperience caused XQ to be further flat, and one dimensional, therefore limiting what YY could also bring with his character. They both appeared rather lacking in certain scenes, and for me, her blank look, or crying actually made YY look like the strong performance here.
I for one don't find YY to be the worst actor, but do agree with comments that his performance can also be better/worse depending on the FL's abilities too.

Themes
This show is rife with propaganda. From the music, to the signs, to the glorification of noble careers such as firefighting and medicine, there are subliminal, and obvious messages about communism throughout the show. I'm aware they left out some key themes from the book such as government corruption etc. which did not sit well with a lot of people.

The one theme/lesson I did really enjoy is SY's ability to let bygones be bygones and not live his life consumed by hatred and revenge. Despite XQ's mother sabotaging him twice in his life - from failing his initial military admission to later setting him up so that he couldn't get a promotion, I respect his ability to live life free from anger. The scene where he's trying to get his cousin Zhai Miao to hand in the footage of Ye Zi, he says "I didn't forgive or forget what the Meng family did to me, I chose not to live my life with hatred". He let it go for himself, not for them.

Music
The music was tried to the propaganda and was all about "respect the party, be disciplined, work hard". While I am not against any of these messages (lesser favourtism towards 'being loyal to the party') it did feel strange to be the backdrop of a show whose main storyline was romance. For me, the music leaned more towards a show regarding their careers.

Ending
I was neutral about the ending. The mother never thanked/apologised to SY which was a big flaw for me, even after he saved her. I was disappointed they didn't show the wedding between SY and XQ and that she went back to her family, unlike the book - I suppose to align with the value of filial piety. Her parents got off scot free.
The secondary characters, such as Jiang Yi and Li Meng, albeit brief, did get some ending. I wished Yanchen/Ye Zi and some of the other characters had more written about them, and what happened next.

Overall, a show with some great positives, but a lot of flaws. Ep 23 onwards is worth rewatching, but it is a show you can skip a lot of. Good if you're a YY fan.