In what order did you play the routes?
I played Kotori, Chihaya, Chizuru, Lucia and Akane. Kotori route was too sad, so when I played Chihaya I found it was better since it wasn't depressing or anything (and Chihaya's "brother" was cool). Chizuru was sad too (the end in particular), Lucia was great (but Kotarou was really dense in that route), and finally Akane route was interesting. I guess it's ok if I don't like the endings since there should be a "true end" with the last 2 routes : I can't wait.
So I'd say Lucia=Chihaya>Akane>Kotori=Chizuru. It's a shame I had to rank Kotori route last when she's the best heroine imo...