I'll admit it - I mostly read it for the art.
Not that the story is bad (it's certainly not great; it's just not bad). But it's not a manga that leaves me on edge, constantly hoping for a new chapter to satisfy my craving. It's also a bit of a dark series, which isn't really my thing, with just barely enough seemingly random bits of humor thrown in to make you keep reading.
But the art. . . I just love it. It's really like nothing I've ever really seen before; the way Maria is drawn is especially beautiful. I probably would have dropped this by now, or never have picked it up, if it wasn't for the artwork.
Other than the art, the only thing I really liked about this series is that the male lead, for once, isn't blatantly obvious. I'm up to volume three, and it still isn't really clear to me which of the two boys Maria will end up with - in most shoujo, you can tell who the ending couple will be from the first chapter. That doesn't happen in Akuma to Love Song.
All in all, it's an alright manga. It's not perfect, and I agree with everyone else that it's getting more and more annoying as it drags on, and it's certainly not up there with, say, Ouran or 1/2 Prince, and it's no where near Hana Kimi. But, it's alright. Read it for the art ^-^
[color=red]Update:[/color] Okay, I got to chapter 45 and just couldn't bring myself to keep going. The characters were annoying and had no depth or development, the plot was predictable and boring, and all in all, it was a stretched, cliche manga that spiraled downhill after the first few volumes. Horribly disappointing, especially because of the fantastic artwork and the promising beginning, both of which are the only reasons this doesn't end up with an even lower rating.