I read it and didn't mind it, but that dosen't mean I'll read this again. Love Monster definately had it's strong and weak points. Sadly, the weak ones are what kept me from really liking this manga.
First of all, the strong points, which is what kept me reading. It was light hearted and funny at times, and made me laugh on occasion. I also didn't mind the plot, although as one reviewer before me has pointed out, it was a little choppy at times. Lastly, it was the mysteries unanwsered in Love Monster that kept me going (i.e. about Hiyo and kurou, which I won't spoil for you), and it is ultimately what made the manga really bearable for me.
Nonetheless, it was the weaknesses about this manga that made it far less enjoyable. The big down side so far about Love Monster is the heroine, who I found myself utterly despising despite my efforts not to. She was just to thinkheaded and silly for me to like her, and the number of times she was rescued and almost sexually assaulted frustrated me no end. The other down side was the smut, which while I don't mind in stories, seemed here a little distasteful here.
I seemed to have ranted about this a little more than I intended. Still, overall I would recommend it. However, if you looking for a supernatural manga along these lines with more likable characters and decent plot, I'd say try Vampire Knight first.