Here are the games that I've rented so far: FF4, DQ5, Dawn of Sorrow and The World Ends with You. The RPGS weren't that great.
FF4 and DQ5 felt archaic and the 3D graphics were

. I wish they had kept the 2d graphics. 3D on the DS simpy look like garbage compared to the PSP.
TWEWY was a little better in presentation but I didn't dig the gameplay or the story.
Luckily, Dawn of Sorrow was pretty fun. I like the fact that it's much closer to Symphony of the Night than Rondo of Blood.
I think I'm gonna buy the whole Castlevania series on the DS. Is there any GBA Castlevania I should be getting as well?