Suki-tte Ii na Yo is a very simple shoujo anime with a mellow and realistic setting. A lot of people compare it to Kimi ni Todoke because of the very similar premise for both shows, but by the end, I felt that KnT took an entirely different direction, focusing on the chase, rather than the post-formation relationship dynamics. Also the side characters are completely different and make the atmosphere completely different, but I digress.
Story: A basic story about a shy, plain girl with no friends, Mei, and a popular boy, Yamato, who fall in love with each other, Suki-tte Ii na Yo has a very character-driven, slow moving plot. Like all stories with a romance at their center, the plot consists mainly of various challenges that appear and cause the characters to change. Most of the challenges to Mei and Yamato's relationship come from within (their personalities, their needs, their past traumas) rather than from without, although there are the token rivals who bump into them and direct the plot for a few episodes.
This story excels is its simplicity. It doesn't focus on "the chase" part of budding relationships as is more common in shoujo anime. Instead, it depicts two high schoolers who are very much in love with each other and shows them learning to negotiate the newness of their relationship, as well as learning to communicate their feelings and expectations for each other. It also contains a fairly small cast of side characters, who similarly develop through their interactions with each other.
It also excels is its realism. Touching oh-so-lightly on societal issues like teenage romance and sex, the dieting and weight issues that go along with self-image and self-conciousness of young women, and a little more heavily on issues of bullying, celebrities dealing with the internet hate machine, and stalking, I thought that the show really gave a good depiction of how tough life as a normal (or not-so-normal) teenager can actually be. Because of this, it set itself apart from the sparkly, everything-is-ok atmospheres that are more typical of shoujo anime.
Characters: What really detracted from the potentially great thematic depth in the plot was the weakness of the characters. Too many of them were too one-dimensional; Megumi was too easy to dislike for her selfishness and Yamato too perfect to really believe: I kept waiting for a flaw of his to be revealed. Obviously the averageness of the other characters served the realism of the show, but at the same time I never really felt that I related strongly to any of them.
Overall, I think this show is quietly good, but it still has a few too many flaws in its characters for me to be able to unreservedly give it above a 7. Still a good watch for shoujo fans, and potentially a good pick for anyone who feels "meh" about shoujo because it's usually so unrealistic.