I don't think this is as good as everybody's saying, nor as bad. It's in between, and corresponds precisely to that 7.4 average score.
Yes, the art is beautiful and the characters are to die for, but that's not nearly enough to get someone interested in a title, right?
The story is indeed super cute and funny at parts. But it's not deep, it's not really original and it really doesn't matter that they are vampires. I mean, from the cover you can already get the feeling - so don't expect too much sexy blood sucking and angsty conflicts about the vampire existence. What I think is important, though, and therefore why I'm not giving it a low score, is that I was interested enough to want to finish it, and I enjoyed the reading.
The characters are not the most complex you'll find out there, but they're quite likable, so it's okay. Kurosu is my favorite, he is totally adorable!
I don't think Yuki's bet is sick or wrong or whatever. He was just insecure, and that's also pretty common in yaoi. I don't know why people get so shocked when facing rape in yaoi or that kind of sexual bet. I mean, they ARE males, and we're seeing from a female point of view - guys do stupid sexual stuff as carelessly as bets. Even worse, they are vampires, so they are probably even more used to that kind of thing. It turned out to be pretty sweet because of the bet anyways, so just chill.
What did bother me was that I liked Mayu-Mayu and Yamada's past together much more than the actual couples or the character's adult versions...they are so cute together and perfect for each other! =/
Anyways, I recommend this if you're just looking for fun and not a remarkable title.