That's about it. This show, and its characters, are wildly popular with fans, and I don't know why. I didn't find much about it interesting.
This anime is derived from a popular 4-panel comic. Humor is largely based on quirks of character -- Yui eats too much, Mio is a scaredy-cat. These jokes are run into the ground, episode after episode. There aren't long story arcs, which is probably a result of the show's origin in a 4-panel strip.
Production values are adequate, but nothing special. Fan service is minmal. Mugi shows some hints of shoujo-ai, which seems obligatory in shounen anime in recent years. Can this stop, please? Along with the maid costumes.
Azumanga Daioh was a simlar show based on a 4-panel strip. Also a fan favorite, and also a show that didn't do much for me, for much the same reasons: un-funny humor, and lack of development of substantial plot, themes, or character. Lucky Star is another recent 4-panel strip with a wildly popular anime developed from it. If you like one of these, you might like the others. And if not, not.