I had Brain Age since launch and I'm still doing it semi-regularly.
I was initially disappointed by the lack of sudoku, which was the main reason why I got the DS ones but I've been finding myself enjoying this Brain Age for what it is. It's been slowly sneaking into my top 10 most played 3DS games. I have a little over 11 hours and don't see myself stopping anytime soon. I only have one more activity left to unlock.
That video above is insane!