This will just be a brief review to kind of collect my thoughts about Kin-iro Mosaic.
Light on content (a la K-On or Tamako Market), thin on plot, and heavy on high-pitched moe and friendship, Kin-iro Mosaic is a fairly average show. There's no overarching plot except developing the girls' friendships, but even that seems light and full of silly jokes.
I think my biggest complaint though, is that I never really believed that Alice and Karen were from Great Britain. Sure they had blonde hair, but they never really acted like Europeans. I can't criticize this point too much, because the show never really aimed to be realistic, but, for me personally, it just jarred with my sense of the characters and made the show a little less enjoyable. (Obviously, it wasn't too bad since I finished it instead of dropping it).
I think if you like cute shows about cute girls doing cute things, and don't really care about plots or deep stories, or just want a light, entertaining, silly show to watch, then you'll really enjoy Kin-iro Mosaic.
It amazes me how similar A channel is to this anime, even the characters are similar, this at first seemed like a bad rehash of the popular anime but the more I watched I realised although it is not as good as A Channel it still has its own good points.
Story: The story is fairly normal for a slice of life anime, nothing much happens and it focuses on one year like most anime of this genre, it is based at around 12 episodes with the possibility of an OVA later on, it mainly focuses on the life in and out of school of 5 school girls with two of the main characters being English (England), this creates a language based plot around the anime, however the idea of a girl from ENGLAND sounding like Google Translate kind of pisses me of and many times through the anime I found myself wanting to rip my ears of, otherwise the anime story wise is fine.
Art: The art in Kiniro Mosaic is almost identical to the type used in A Channel, it may also to some people resemble the art in love lab, this art is cutesy and fairly normal for a slice of life like this one, the art itself has no effect on the anime other than extenuating cute features.
Sound: Not really much I can say about this really, the OP isn't bad but isn't nearly as good as some of the more recent and memorable anime. The ED is pretty good though and takes a leaf out of many slice of life anime and has the ED as the main characters singing and dancing together which works pretty well but other than that there are no real scenes where sound becomes important of all that great. In terms of voice acting that a whole different thing, it’s fine until the girls (who are apparently native to England) start sounding like bloody Google Translate and then my ears bleed but other than that its fine, and actually pretty cute.
Character: the characters are similar to the characters of A channel but there are not many other defining features in the characters, there is not much time spent on back story so not much of the characters life gets revealed.
Enjoyment/Overall: This anime was pretty enjoyable, I usually score anime high so if you are into anime as much as me I would take like 2 points off to get it to a reasonable score, as you can tell my biggest problem with the anime was the continuous use of bad English throughout it but other than that it was just another slice of life which means in lay-man’s terms "It doesn't really matter what happened in the anime, the fact is it happened and it's not the end of the world if it didn't work out."