From the Media-Create data for the week of March 16 to March 22 (ie: the first week of sales), Amagami ranked at #3 in Japan with 42 000 units sold
As for the character designs, even though everyone does look similar, I wasn't really distracted by that. What drew me to the game was the solid seiyuu cast that voiced the various characters. It includes Shizuka Itou (Hinagiku in Hayate no Gotoku), Rina Satou (Haruka in Minami-ke and Mikoto in To Aru Majutsu no Index) and yukana (C.C. in Code Geass) <3