Im glad it was delayed, gave me time to play other Devil Survivors on the DS and realized the gameplay is not for me at all.
The gameplay of SMT IV is not that close to that of Devil Survivor.
DS is a tactical, SMT IV a traditionnal turn based jRPG.
Edit: That said, like many SMT games (especially post-Nocturne), the skills and demons remain mainly the same, and the combat system gravitates around the use of strength/weaknesses, with an encouraged use of the fusion system.