In my paper there's a note. It's written by a journalist, not anyone working with the report. This is a rough translation.
The leader of the "fitness crew" and the crew itself is unable to find any proof that Wii Fit is superior to a gym. The gym offers a 1/3 better burn rate than Wii Fit. Wii Fit is therefore only 75% as efficient as a gym.
Edit: Argh, less than a minute too late.
http://www.vgchartz.com/games/userreviewdisp.php?id=261
That is VGChartz LONGEST review. And it's NOT Cute Kitten DS