Aoishiro was my first ever Visual Novel. Since then, i've played quite a few, and in my eyes, non can compare. Sure, it dosen't have the depth of Clannad, or Fate, but it more then makes up for it with it's amazing visuals, excellent soundtrack, great characters, and stellar story, which is a mix of mystery, horror, and light Romance (Extra points for being YURI) I've played it countless times, I loved it so much I imported the limited version from Japan for the hell of it. It's just so fun to play. My favorite routes (There's six if you count Grand) are Grand and Nami, but all of them are excellent (even if Yasumi is slightly annoying), and it's a really big VN (with 56 endings.) Better yet, you actually have to work very hard to get the good endings, which many VN'S tend to give on a silver platter. It's production value is amazing, as mentioned before, it has by far the best visuals in a VN ...ever, it's fully voiced with high quality voice actors, and an excellent sound track. It looks as good as a high budget Anime.
If you haven't played it before, do it. It's well worth the time to experience this master piece.
10/10 Overall (Best VN i've played.)