I've just finished "Moonshadow".
The story certainly had potential and it started off quite strongly, even though the plot developed slowly. But as the episodes progressed, I found it became increasingly draggy, and my interest was fading. I just don't think the writing was particularly good, especially after the early few episodes. The end result was a drama although it started off strongly, ended up being quite bland.
I don't think it is as bad as some reviewers and commentors have claimed. I'd call it "average" or "mediocre" as opposed to "terrible", and I'd still recommend it to fans of Thai GL dramas, but perhaps not to general drama watchers.