3DS is no DS, but it will end up selling better than the PSP for sure, and sell a ton of Nintendo software with it, which is good for Nintendo.
Wii U, I think is going to be a relative flop. I don't think Nintendo knows what they're doing in the console space and they really haven't for several years now (see the Wii losing most of its market momentum as well). They will lose their casual base and have mostly just Nintendo fans left to sell to.
I think the Wii U really will perform like a modern GameCube-N64, but the market is so much bigger today that a modern GameCube probably translates to about 35-40+ million users IMO.
Internally I believe Nintendo is already under way with the development of a console-portable hybrid platform, which could be fast tracked if Nintendo decides the Wii U isn't getting the job done. ARM processors and portable processors in general are growing in horsepower by leaps and bounds every year it seems.
