Not quite as good as the others, but still great!
Unfortunately this game is probably one of the worst in series. That doesn't mean it's bad though, it's great. Saying it's the worst is like comparing an A- grade to an A grade, but it still doesn't quite reach the magic that at least 4 of the other 6 games did.
The level design is not quite as polished and imaginative as the other Castlevania games. Here you will find pretty straightforward corridors, and hub-style level design, which I feel doesn't work here. That's if you compare the games though, and I'm being picky, I know. It's just that these games are so great, and I expect an extremely high standard that they have set for themselves. This one is almost there, but is slightly below the average.
If I don't compare, on its own, this game shines. The music, the graphics, and the deep RPG, Metroid style gameplay are not to be missed. The boss battles are especially fun. This game is also very long! Longer than most of the handheld Castlevania games.
If you have a DS, and you like the other Castlevania games, you should get this one, period. If you've never played a Castlevania game since SoTN, start from the beginning and play all 6, you will be impressed.