What can I say, I bought it for the Sudoku.
To date, the Sudoku within Brain Age has one of the best designs. The handwriting recognition is very good and the ability to write in hints and have them show on the game board makes this handheld version of Sudoku the closest to actual paper and pencil without the mess.
Unfortunately, there are a limited number of Sudoku games and often, when you restart Brain Age, it will force you to do drawing exercises before it will allow you to play a new Sudoku game. While that seems like a good way to "train your brain" if I only have 30 minutes to play, I want to get to the puzzles and not be sidetracked by these other options.
The other brain training exercises are great refreshers but quickly lose their appeal for replay. More Sudoku, please and less "brain training".