Just finished all the routes and the only one I found a bit lacking was Makina's. The rest were much fuller it seemed with the back story of their characters. I would say Sachi's was the best but Michiru's , Yumiko's, Amane's were also very moving and yes I did shed a tear or two more then a few times in different routes.
It takes a bit to play through all of it but well worth it in my opinion. A pretty good way to get lost for a bit of time and forget your troubles.