While Nintendo do make sequels (Well duh, they're a business), they at least try new things, not just same mechanics in a new setting (for the most part)
Also, yes the 3DS is the same price as a PS3, a PS3 now, not a PS3 launch. The 3DS is a lot of high tech stuff wrapped in a little box including 3D and Touch capable screens, batteries etc. The PS3 is just some more high tech equipment with outputs.