Unlike some people above me, I really liked this manga, and that's exactly because it's different. The main characters are different, than in common shoujo mangas, the plot seems to be pretty normal, but in the end, the story often moves in the opposite dirrection, then you expect. Some people call that unrealistic, but I think it's just original. I mean, 99 of 100 shoujo heroins would dump the guy imediately, if they knew, he was involved with other women(and that even in case it was just in the past, and not actual at all...), and I guess we all read it and hope, that now she'll treat him the way he deserves it, and dump him, and he would be depressed, tries to apologise, does something incredible to make her forgive him and so on and so on... but isn't it already a very common and often used scenario? I think it's much more interesting the way it was made, cause in real life you don't have such ideal guys running all over the world, and you have to try hard to be with the one you love and to maintain the relationship, though it would be really nice if you just could run off sulking by every problem, while the man would chase after you trying his best to win you back XD Yeah, the main hero is really not a typical shoujo knight on a white horse. He's nothing like the type "Oh, I fell in love with her, and will love her and only her for the rest of my life and will do anything for her". Or at least he wasn't that way till the late chapters. He doesn't mind saying something that hurts her, and it's not unintentional at all. He isn't perfect and doesn't have ideal reasons for his behaviour all the time. Well, he's a teenager after all... When I read shoujo manga, I almost forget, that teenagers aren't really perfect men in each aspect XD

And about that issue of wrong message, that is mentioned in the first review... I think, the message is totaly ok. Because it really says that most people can do something about their looks, if they have the will and put some efforts into it. Of course, if the people want to. And it's no use just blaming everything in the world on the looks, or covering own laziness with ideals like "looks don't matter if the person is good inside". I mean, of course it does count what's inside, but it doesn't mean people can use it as an excuse for not doing anything about the outside. If someone doesn't feel good about his looks, he should just do something so he would be content with himself, why should it be so wrong?
If this manga sends wrong message, then what about all the other shoujo manga? The people there are always cute or beautifull, does that mean they say that ugly people have no chance in love at all? XD

And finally, probably one of the most important reasons for me liking the manga, is the fact, that it's really funny. I mean, most of shoujo mangas are just romantic. Well, they try to be funny, but it's pretty hard to not to end by those cliche jokes, that are everywhere, and are not funny at all anymore... Just the moment during their scholl trip: "I don't have money for a love hotel! - So let's earn it! Hey, foreigner, buy this, see, it's a japanese item, the sign say's "National treasure"" :D It's really rare coming across a funny romantic manga. So I think Doubt!! is really good one, in every aspect.