This review is going to be broken down into the 5 parts that MAL focuses on with each section getting critiqued.
As you know by the description on the anime's page, K-on is suppose to be about Yui Hirasawa and joining of saving of her high school's light music club, with the problem being that Yui has never read music or knows how to play a guitar. Slowly a few of these problems get cleared up but the main bulk of the plot goes no where whatsoever. You can come in at any episode and still get what's going. The anime is heavy on the theme "light and fluffy." to which when watching it you don't have to know anything nor necessarily be there the entire episode to know what is going to happen and that's the main problem, like every other "moe" anime it's generic and predictable in the events category.
This is probably the biggest problem with the show in my opinion, the art. Seriously I can guarantee you that the studio used a step by step handbook and stencil set to create yui, mio, ristu and mugi, it's what is seriously killing the industry today in my opinion...generic characters. There is nothing that makes any one character in K-on stand out. The backgrounds themselves are nothing to praise about either as they are the standard school, bustling street/shop and from time to time inside one of the girls home scenes. To sum it up the art lacks originality and there is no direction for it.
This is probably the only place that K-on climbs up outta the rubbish category. The times that you hear music made by the club it's actually not that bad and can be catchy at times, and with it's suppose plot revolving around music you'd think to hear it a lot but it's quite the opposite, the girls spend more time sitting around being airheads then trying to do anything music related.
What can I say,all of the characters of K-on have traits that superficial. They all are generic and no one has anything that makes them unique or stand out.
After watching 13 episodes, I can say overall the enjoyment was just another thing including original art and characters that the show was missing...I mean it was boring and painful as well as predictable to watch.
K-on is a light and fluffy fan service anime to which it hosts no original art and set of characters. If your looking for something to which you don't need to think or understand maybe you'd enjoy k-on but even then your going to have to endure lackluster scenes of boring pointless conversations to which watching windows screen saver can provide more enjoyment.