If I had to sum up all of Nichijou in one word, it would be "beautiful." As a slice of life, this anime can't be for everyone, as most people like to have a story that is actually driven by the plot. But even if you aren't into slice of life anime, there is something in Nichijou for everyone to enjoy.
Every episode is a series of semi-random "moments" in each of the characters' lives. As far as an actual storyline goes, there is no distinct beginning or end to Nichijou. No goal, no real conflict - as to be expected of a slice of life, "storyless." However, at about the halfway point, I started to question whether all of Nichijou somewhat revolves around Nano and her dreams of leading a normal, everyday life (which is what "nichijou" roughly translates to). There are some really beautiful moments that do advance the plot, which is part of what makes Nichijou so special as a slice of life.
Stunning. Characters are distinct, cute, and thoroughly enjoyable to look at. Animation has very fluid movements, and the "camera" work, especially during the funny scenes, is just brilliant. One thing that I particularly adore about this anime is the fact that, as opposed to some anime like Fullmetal Alchemist Brotherhood, in which the art style becomes overly-simplistic during moments of comedy, Nichijou's art style becomes vastly more serious and dramatic for almost all of the hilarious moments. Without losing an ounce of fluidity, Nichijou will abruptly switch from cute and colorful to intense, fast-paced action with over-the-top explosions and yelling. Everything about the art in this anime is something to behold.
Hats off to Hyadain, as he did both of the OP songs and one of the ED songs, which are fun and upbeat, as expected of him. The background music is also very well-done, it's unobtrusive and mellow, allowing the characters themselves to set the mood more so than the music.
This is the glue that holds the entire thing together. The characters make up for the lack of a concrete story and then some - this anime is definitely NOT just something pretty to look at. During the few times that the plot progresses, so do the characters. They learn and grow, they have problems and they help each other. I found myself growing attached to all of the characters, I don't think there is a bad one in the bunch.
Overall, I love this anime. It is certainly beautiful in more ways than one, and it stands above many other anime in terms of being a slice of life and a comedy. If you like Lucky Star and Gintama, I can almost assure you that you'll have a blast with this anime. I know I sure did!