I personally find the Western stories to be cringey. The art for them is fine in most cases, but the stories (especially the Mature ones) make me want to die due to the way they are written. The BDSM ones cause my soul to leave my body--not because I dislike these types of stories, but because I find them to be written in an embarrassing way. Everything seems to be a punchline or too heavyhanded. I dont mind explicit content, but there's always room for a little subtlety.
The stories adapted from WebToon or Naver have FAR prettier art and the writing is much more satisfying. They leave you craving more, aching for the next chapter. The drama is typically better paced. The humor doesn't make you roll your eyes.
I recommend reading a chapter of a book using the free points to see if you like it, and then if you can afford it, buy the whole thing outright. You'll be able to replay the story as many times as you like (great if there's multiple romance options) and you'll have access to all the clothes for all the characters!