Amagami SS in short is probably the best adaption of a dating sim that stays true to its roots while feeling like it was from a collection of stories rather than a game. Each arc is wonderful to watch and fulfills the story for the viewer, in the end even actually expanding on it.
Story: 10/10 It is in omnibus format meaning that the stories may contain the same characters but every four episodes they "reset" and focus on another aspect (in this case a girl) and expand the story on these "what if" moments. Overall very enjoyable each arc had it's differences and no two arcs were alike. The only similarity is the relationship building and character placing that occurred. That being said, each arc feels unique and enjoyable.
Art: 8/10 Amagami SS isn't the greatest anime in terms of art I have seen, but in no means does it try to be that. The character movements are fluid and what you would expect from art style today, neither amazing or bad.
Sound: 10/10 The OP's this series contains are among my favorite openings I have encountered while watching anime, as well as each ending theme for each girls arc is performed by the voice actress which I just found incredible. A few of the endings are so catchy I can play them on repeat even. In terms of the sound quality during the anime it is what you would expect from this type of show, however in some scenes the background sounds and music just make the experience much more enjoyable than most Anime I have seen. And to make an example, don't worry not a spoiler, but during a scene the sounds of the voices actually echo to show how empty/large the room actually is I haven't been that impressed for a while. (I know it's sad)
Characters: 10/10 The 6 girls are all incredible in their own ways while the male lead isn't a terrible guy either, he is actually rather likable, indecisive occasionally but firm in what he thinks and should do most of the time. As for the girls they each have unique personalities and are all interesting in their own way. I will explain the girls below in the order that their arcs came.
Haruka Morishima: The school idol, very outgoing and caring as well as has an overall incredible personality. (My personal favorite)
Kaoru Tanamachi: The tomboyish but feminine in a sense long time friend, very funny as well.
Sae Nakata: The very shy, reserved, quiet girl. Not much to say other than her voice may be perceived as annoying. (I personally do think so too. But it doesn't take away from the arc)
Ai Nanasaki: An underclassman on the swim team, seems cold at first but warms up to MC, great personality not afraid to say what she thinks.
Rihoko Sakurai: The childhood friend, she is gentle and caring as well as somewhat ditzy at sometimes, great character as well. (Will need to watch second season for more development if this is your favorite character.)
Tsukasa Ayatsuji: Definitely the most interesting arc as well as character, being the Class Rep and a perfectionist with a few twists and turns along the way. This arc is a must watch, the character development in four episodes is amazing, I can't say enough.
Enjoyment: 10/10 This will probably stay my favorite anime of all time I can't express enough of how much I enjoyed this series as a whole and how it stayed so true to form and how so much development of the characters could be done in four episodes while some take at least 3x that amount to get somewhere in romance.
tl;dr Just watch it, all of it. Just once.