Variety of games, lots of games and continued support of the console until the gen ends.
MS is notorious for slowing down support in the last 12-18 months of a consoles life. Nintendo this gen has been pretty lacking with quality 1st party games. They screwed up Lylat Wars and Metroid as well.
Whoever said life to be like a box of chocolates clearly didn't know what he was talking about.
Life is more like a game of bumper cars. At every turn there is a possibility you will get screwed.