I'm a Wii owner and enthusiast. It doesn't have the graphic capabilities of the other two, but it has the best control and most fun gameplay in my opinion. I play 360 and PS3 alot, my friends have 'em, but I'm always happy to go home to my Wii.
Besides, a Madden where you actually have to THROW the football? 'Nuff said.
With that said, to each there own. Some like others more. Just get your kid which one they want. (Unless you don't want to shell out $500 for the PS3!!)