This is a straight slice of life series. There is no significant focus on romance, action, mystery, etc. In fact, if you're looking for something with just a continuous plot you should look elsewhere. If you're looking to kill time watching moe/yuri girls interact then this is your series. Take this review with a grain of salt as I wasn't a huge fan of either Lucky Star, Hyakko, or K-on.
Animation:
Animation is a bit of a mixed bag here. The primary characters' styling is cute if a bit thin. Backgrounds are a mix between really nice drawings and cartoony scenery either consisting of simple solid colors or even occasionally crayon-styled sketches. While these scenes serve a purpose (when you're in a character's thoughts), I still don't like the extensive use. As this is a pure slice of life, there isn't too much action, there is no blood/gore, and there is no ecchi (come on the cast is practically all-girl). There is a lot of girls talking; yes, a lot of mouths move, occasionally the bodies will as well.
Sound:
The OP is light, which fits with the series well; though I personally like more energetic or peaceful pieces. The ED is even more fluffy than the OP, the track almost remind me of Raison d'etre from Chobits; though being a Rie Tanaka fan I have to say the latter is much better. The BGM is likewise very light and very mixed with guitars, harmonicas, and pianos. A unique feature of this series is the use of group insert songs, which remind me of television programming for toddlers. I really loathed these.
The entire purpose of this show is having the girls talk to each other and the VAs do a great job fitting a voice to the character personalities. Run sounds as ditzy as she acts and Minako Kotobuki does a great job giving Yuuko an accent (see if you can notice it).
Story:
The story consists of girls doing stuff such as interacting at school, interacting at a local diner, interacting while shopping, and interacting in general. The series are purely episodic, the only thing to give a continuity to the ordering is the passing of the seasons. There really isn't much of an underlying plot as the focus is purely on the characters. There might have been one or two comedic moments but I'm senses are still probably recovering from the overload that is Nichijou.
Character:
Each of the four girls has a unique, and very distinguishing personality. The majority of the enjoyment in this series will derive from how these personalities interact. What is a bit confusing is the somewhat yuri behavior Touru displays towards the clueless Run. While it is true that you get a lot of character interaction, you don't really get any development. The characters start as friends, occasionally get into minor quarrels, and then end up as, well, friends.
Value:
While I could try to embellish a description by saying this series shows the greatness of friendship, it doesn't even do quite that.
Minami-ke, Hyakko, Lucky Star, and K-On all distinguish themselves in very clear ways (see those reviews for details). However, I can't find what distinguishes this series other than its impeccable ability to not have any tension. It's simply a show about hanging out and having a good time.
