If K-ON! is the future of slice-of-life moe anime, then the genre is dying. Now, I myself am personally a great fan of the niche genre and have delighted in viewing many anime falling under it, no matter how silly or inane. That's because I don't mind having to turn off my brain to enjoy anime, but I expect to be compensated for doing so, be it by making me laugh, warming my heart, or leaving me with something to remember. K-ON! splendidly failed in all three ways multiple times throughout, and came off as a shoddy effort all around.
Because a slice-of-life moe series is often devoid of any ongoing plot of significant importance, it must rely on the day-to-day circumstances of the characters, presenting them in new and inventive, yet somewhat familiar ways in order to keep attention. Surprisingly enough, K-ON! follows a linear, though loosely connected story, but does nothing of interest with the day-to-day circumstances. It's as if the staff decided that it was okay for the girls to be lazy and uneventful because it's slice-of-life, to which I must say "NO NO NO"... had to get that out of the way. I'll be serious now.
Likewise, the characters need to be interesting enough to actively engage in following their exploits. Harsh as it may be to say, it was a waste of time to follow around a main character like Yui. I could rant for hours on end about Yui, but to sum her up, she's a mentally challenged nutcase. Now, I can excuse character stupidity as long as the main character has qualities that redeem said stupidity, be it fierce independence, reliability, or if it's made clear she's meant to be the butt of everyone's joke. Yui has none of these qualities. She is an idiot, and no one ever discourages her from being an idiot. Minor spoiler alert, but it must be said... I am absolutely furious at the gall the staff had to have Yui comment in Ep. 12 about how much she has changed. In the entire series, she does not grow even a little. What a crock.
Enough about Yui though, there are other characters to focus on; all of who range from average to above-average. They're all likeable too, but far too simplistic. With no real inventiveness to the situations they end up in as previously stated, I had expected their personalities to be clever enough to make up for that lack. In this, the staff succeeds to a degree, but nothing comes from it. Everyone is essentially the same at the beginning as they are at the end and there is very little proof that any of them have grown as friends, regardless of what the series wants us to believe.
In the matter of technical aspects, K-ON!'s fluidity is remarkable but the style is such that it comes off incredibly choppy, and at some points downright ugly. It felt as though Kyoto Animation spent a ton on making it fluid and in doing so, took from the budget that allowed for the actual artwork itself, excusing the instruments which often look better than the girls themselves. While this tradeoff doesn't work entirely, it could be far worse. In addition, because this tradeoff comes from animation maestro Kyoto Animation, it is doubly worse.
Though this is a show about a music club, the BGM is boring. Thankfully, a killer OP/ED combo and some fantastic inserts make up for that. On the acting front,the amateur seiyuu all sound like younger versions of already successful seiyuu, like how Mio's seiyuu Yoko Hirasa sounds not-too-surprisingly like a younger Aya Hirano. This isn't to criticize their talents, though. The fact that these newcomers are so lively and fits their character perfectly from the start is a compliment, one of the few I have given the series.
From all of the above, K-ON! to me came off as a cheap way for Kyoto Animation and Pony Canyon to make money. There is little effort, the characters are rather flat and unchanging, and everything in the news about it from merchandise tie-ins to Oricon charts leads me to believe it's one giant marketing ploy rather than an honest effort of a series. For this, I cannot say I enjoyed all of it, though it was good sporadically. However, as I said in the beginning, if these shoddy attempts at slice-of-life moe are what we as anime viewers choose to support and demand more of, we are killing the genre as we speak.
Overall, I give K-ON! a 6 out of 10.