Story
There's no general story in the anime. Instead every episode is a short story about some event. Usually it's about something an event/situation inside the school. Since it's about events it doesn't exactly follow a specific character around. This makes it more approachable for people who don't like one character. It's possible that if you don't enjoy one episode because you don't like a specific character, you might like the next one. The series start in the fall, you get to see a couple of events till the end of the year.
A couple of examples of events/situations are, a girl trying to figure out how to get control her weight. In case you wondered why this would be interesting, it's not really. However through her actions and interactions she'll bond with people and work together with them, which is heart warming in the end. A second example is a story how 2 seemingly polar opposite girls became friends. Although they had nothing in common, they met and through the circumstances they become best friends. Ofcourse there were some set backs which makes the little story a bit more interesting than "I came, I conquered".
Characters
Almost the entire (active) cast of GF is made up out of high school girls from the same school. According to MAL there are 5 main characters. I would say that the five mentioned on MAL have more screen time than the remaining characters. But since there's no actual character followed as main character, all the girls sort of all feel equally important every time a new episode starts. The about 35 "non-main character girls" or so have less screen time and tend to move around in groups a bit more. This results in them having seemingly shallower characters. Some of them (or groups) will get a spotlight in certain episodes while others are only following a supporting role.
This results diverse episodes, which make episodes still enjoyable even if you happen to not really like certain characters. Even if you don't really like one of the five main character girls, you don't follow them every single episode. Also every girl has a different voice actress, this is pretty nice since there are lots of different girls. I personally think it makes the girls more diverse.
Art, the art is OK. It's not amazing, but typically what you expect to see in a cute girls doing cute things type of anime. With lower than average details. Basically, what you see is what you get. There's not a lot on the screen so basically if there's no reason for a prop to be on the screen, it's basically not there. There are no eye candy unused water bottles on tables for example. Counters are neat and don't have anything on them. So you shouldn't really expect exceptional art. I would say it's not above average of what you would expect in 2014. The animation is sort of not that great too. A lot is rather static. When something does move it might not move very fluently or natural. If you're not easily bothered by this, I think it wont pose a problem.
Sound
The sound is good. Voice actresses sound different, music plays at the right times so it doesn't fall silent. The music sounds how you expect it to sound and usually enforces the atmosphere, but it doesn't ever reach the level where I would say "wow this sounds amazing". But that's not needed, the music fits and does its job.
My general experience and opinions on the anime
I think that most of the little stories were really nice to watch. I did like some characters more than others, so episodes containing more girls I liked vs characters I didn't really care for would obviously be more fun for me. But every episode was fun to watch. The conclusion of each episode would always give me the feeling I wasn't wasting time. Eventhough it's predictable at times just experiencing the stories was good enough for me.
The next section will be a comparison with similar healing anime. So you can see how I think GF relates to them.
The Aria series (the Animation, Natural and Origination) and Non Non Biyori are better in my eyes. Aria follows a couple of characters going on "adventure" or experiencing something amazing every episode. Aria had a nice and consistent pacing which fit the anime perfectly. It also had music which stood out positively enforcing the mood/atmosphere a lot better than GF. Also Aria was more touching in general while like in GF not trying to go overboard with drama. Aria was a wonderful experience, whereas GF was merely very nice.
Non Non Biyori is similar to GF in cuteness in art style. It also is comedic, but Non Non Biyori does the comedy better. Non Non Biyori also has more screen time for the characters giving them a deeper character.
Both anime have a higher emphesis on art. Both of them have tried to put the scenery in detail. While Aria is older and the art I guess outdated, it was good enough for me to fill in the amazingness of the scenery with what they provided me.
But all hope isn't lost! It's still better than some in my eyes! Keep in mind that I haven't finished Gochuumon wa Usagi Desu ka? (Gochuumon), K-ON second season and Hanayamata. Actually all 3 of them have the same reason why I haven't been able to finish them. They all try to shove down your throat that the girls are cute and moe. This is reflected in what happens in the anime. In Hanayamata for example there's this girl that keeps tripping over and falling flat on her face. If it happens it's fine. But when it happens for no reason it annoys me. Secondly they put the emphesis on it and put it in the center of attention. While it might not be annoying to some of you, to me it seems as if they're trying to hide their lack of content with some kind of filler. Again this might not be bad if it's used in the right context or change the mood, but when it happens so something happens it annoys me. GF doesn't do this. In GF the girls all do what they normally would. Do they do it in a cute way? Well the director lets us decided wether we think it's cute or not. This makes the show a lot more enjoyable for me. So basically GF let's us decided what we think of things rather than forcing us to adopt his opinion.
K-ON! is a step up in art and story compared to Hanayamata. Gochuumon is a a couple of steps up in art compared to... well anything else mentioned but story-wise it's not that awesome. But unfortunately I couldn't deal with the "I present you lots of cuteness, accept that it's cute and deal with it" attitude. So if you're actually fine with an overdose of cuteness you might like the 3 above mentioned series (and Kiniro Mosaic) better than GF.
Reasons to watch:
Wanting to enjoy a relaxed 20 minutes and feel good afterwards.
Liking cute girls.
Reasons not to watch:
Effectively no plot.
Low progress.
Low development of characters.
No top quality art.
Sometimes not fluent animation.
Not liking some voice actresses.
Predictablity.
Kokomi's overly sized udders (I still don't understand why her breasts seem so huge).
I hope you got an idea wether you should watch it or not. In the end it really boils down to wether you only want to relax and watch that episode and feel good at the end, without any expectation of grandness.
Anyway my final verdict for GF is an 8. This means I enjoyed it quite a bit. There are definately better things out there, but I don't regret watching Girlfriend (Kari).
