@Ra.zz I second that. I liked both of them.
Now Coming to which stories I believe are likely to Win.
Heart:
The Monster Under The Bed(9.86) I liked it very much. Rooting for this to win. 
Leona the Werewolf (9.33): Its good but I didn't like it very much. Still, its a likely contender.
Brain:
Poor Soul(9.03): I dont like this, but its really popular.
Red Dart(9.85): I think it is the best in Brain and I dont see much competion Quality-wise. Has decent ausience-interaction, so I am rooting for this.
Reasons:
I dont think Webtoon actually places a lot of Emphasis on Quality Stories. So, only once a story is popular enough, things like Quality will come in. Otherwise stories like Lets Play and True Beauty would not be that popular and marketed. While something like Spirit Fingers in the same genre is almost unknown. (Its miles better than either of them).
Taking that into consideration, I believe that, The Monster Under The Bed(9.86) is the front runner in Heart category. It is among my Top 5 reads in the Top Story Contest, and I personally believe it is the Best. There are other stories which are of similar-level, but Monster Under My Bed wins based on Audience.
It has the best Audience Engagement along with Leona and its objectively better than Leona(9.33). And I think, Webtoon places a lot of emphasis on Subscribers and Likes.
It is the only popular story (by likes) among top 20 which doesn't have 5 episodes!!
So, Leona is also a contender to Win tho there are better stories imo.
And same reasons for Brain Category.