Heard different different things from different people,, can't really decide well about it....I really need some specific reasons to why the drama/webtoon rather than webtoon/drama? 

MDL - MAL

Actually, I've started watching drama, but didn't like the series at all. Can say nothing about webtoon

I started the drama but dropped it at ep 2 idk why I just didn't got hooked by the ML at all but the FL is pretty sweet

Webtoon.
I was not a fan of the drama. But I have to say I read the webtoon before watching the drama so that may have impacted my expectations and thus my disappointment.

I honestly love this drama but the man undergoes a huge character development as the show goes on. He is clearly has narcissistic tendency because he has grown up believing that it's him against the world and so because of that he thinks the world is  eat or get eaten. I don't know. I like his character growth and the story.