I've read some opinions here and there in this comment section. It was either shot down or rated very high. But in the end it seems that even those who disliked the way this manhwa is, had very strong reactions to it. And that could also meany that this work really got to the reader.
I myself was hooked after a while. Even though it was difficult read at first (didn't read that many manhwa before). It's true that it's sometimes overly dramatic, but that's the thing with manhwa and korean works. They specialize in drama and either you like that or not. But at leasts it's GOOD drama and focus' on points some manga would just overlook and do go into depth. It was funny at first, but not really a little bit later. Go read some japanese lovecom if you want only something to laugh and a bit (or more) of romance. Faeries Landing was like that at first too, but like with Unbalance at the later points it made you go "Woah...heavy".
As for me I like this drama stuff and the "romance". It's not overly cliché or with an unrealistic pace. I mean there are only about 75 chapters out and there was more plot and (character) developement than in your typical harem love-come. It's a different style, so if you think it's too slow, think again. At least something happens. (even though comparing it to manga'S as To-Love-Ru is a bad move, it had more developement in one volume than the whole to-love-ru series).
Okay so the main plot with the student teacher relationship isn't moving that fast for some people... hey at least they give as some decent reasons for that. And if you don't like the twist and drama don't read Manhwa (especially by Im Dal Young).
Thus I give it a 9/10 rating. The rating was also influenced by the AWESOME Art of Lee Soo Hyun. I absolutely can't understand how anyone glances to cowslaves can not like the art. Soo Hyun does some really good art (if you got decent HQ scanlation you can see it all the better) and some japanese artists/mangaka just plain suck in comparison (even if their story is good/interesting).