The best part of the DS version was the enhanced realistic factor that seeped in. It was better both in terms of visual display and sound track. The appearance of the whole game was improved and every minute details could be easily recognized. The characters showed an improved animated style which further acted as a feather in the cap.
I have still not really gotten used to the 3DS but I also have not given it much effort, even with FF games. I am glad to hear that things are imprved, though. Its pretty impressive how realistic it can appear.
I used to play Final Fantasy IV in the DS platform and I enjoy playing it, its one of a kind rpg in its time when the first time it was release. I started the After years in pc but I'm not able to finish the game though but I like the story back in the first chapter of the game. On the 3ds, I think the game will be more interesting and a better gameplay but I haven't played it yet.