I'm still playing Ys during my free time, and really enjoyed Celceta. Started Felghana but it didn't click (even if it's the same engine as Origin, which I liked). Moved on to Dana and while it's cool, I'm starting to get tired of it. Parts of the plot drag on too much.
Parts of the plot drag on too much and, for some reason the combat isn't clicking with me. It's basically the same system as Celceta, but I felt that the combat there was more fun than in Dana. Still not sure why, tho.