I have not seen the Korean drama or read the original webtoon, so I cannot compare them to this Japanese version. Nevertheless, this version has a distinctly "Korean feel" to it. Especially the love triangle (quadrangle?) and the fight against a power-hungry chairman of a huge conglomerate are plot points I've seen in several Korean dramas.
(But I trust that the story was Japanese enough for the Japanese producers to make an adaptation.)

I liked the basic idea of a young man seeking revenge for a wrong done to him and his father -- with the help of friends he makes along the way.
(I wonder; if this had been an original idea, what would a Japanese writer have done with it? More friendship and group action, less love triangle, I hope.)
Also, the pacing and story managed to keep my interest until the four-year time skip. After that, I found a lot of the plot points superfluous and the rest dragged on.)

--spoilers start here--

I also did not like most of the characters:
* Aoi who was introduced as a high school brat, is suddenly a more than capable manager? At twenty? I find that not believable, especially as her main motivation is her "love" for Arata -- which feels more like a childish crush to me.
* Arata who is supposed to have strong morals, and put people before profit in the first episodes, becomes more and more ruthless and lives only for his revenge -- he even has no answer to the question "What are you going to do after?" for most of the series. That character devolpment could have been interseting but then they should have addressed it more.
* Riku, who was fine as a character, but until her surgery looked more like a FTM transgender person than a MTF transgender person. Also, why did they choose a biologically female actress? Were there no adequate male actors willing to play her? (I have no idea whether there are actual transgender actors in Japan who could have taken the role, which would have been the best choice.)
* Yuka was interesting for a lot of the episodes, because her actions were rather ambiguous. She was a character with shades of grey -- but unfortunately she was also too passive, waiting for Arata to "save her", whatever that meant.
* Ryota, the ex-criminal, had not enough screen time to develop his character. He's an example why I am not fond of time jumps -- what happened to him in the time when RC grew and he had to change his position? He started a an uneducated ruffian -- how did he manage to change to managing director?
* The one I felt the most sympathy for was Ryuji, who was the most likeable among the bunch. But why does his only reason for doing what he does have to be his "One True Love"(TM)? There are so many other motivations than that!

The Nagayas (father and elder son) were fantastic enemies though! No complaints here!

All in all, I do not regret watching it, but I wouldn't necessarily recommend it to others -- there are better dramas out there.