After finishing To Love Ru, I jumped into Darkness.
First of all, the ecchi here is a lot heavier then in the classic To Love Ru not only because the nipples are drawn, but also due to the events that happen (like Rito kissing Lala's "lower lips" multiple times during the manga) and you know what, I like it. I always felt that it's better to have no censor than to have things like hair censoring nipples or convinently placed object in front of X part. Anyway, that's one thing I think Darkness did better.
Another thing was the story. The classic To Love Ru manga had little to no story (save for some chapters), but this one has a story from chapter one up to the end. Basically, we can divide the story into two parts, before Darkness transformation and after Darkness transformation.
Before the Darkness transformation, Momo decides to make Rito's harem, but there are many obstacles in her way, such as Yami having Rito as a target, Mea and Nemessis' plan to turn Yami into Darkness and also who whould take part in the harem. It doesn't take long for there to be some many candidates for the harem that one has to wonder of Rito will survive the honey moon.
After the Darkness transformation, it's time for everyone to change. Everyone begins to work, on their own way, towards the harem, though many don't even realise that. In the final chapters of the manga, Rito is troubled if he should or not accept his harem. Whle he does see it as the only solution for eveyone to be happy, he doesn't accept it at his core, so there are still more troubles to come.
Other than that, there's not much to say. The comedy if funny, the ecchi is good, the characters aren't anoying. Really, is there a reason to dislike this?
(spoiler, by the end of the manga, Rito and Haruna do confess to each other)