I also like the fact that it is small...
Can bring it anywhere, and it doesn't weigh much, either.
I don't like the fact that the USB slots are at the back, my wii is on a shelf where you have to fit your arm through a small area to get to the back of the wii
One con about the Wii is the controller options, some games are just not made for the Wiimote with its features, I think developers should have included an option in the games to either use the Wiimote with its motion, Classic controller or Gamecube controller, like Mortal Kombat does, this way some of the games will be so much better.
Just because the motion is there you shouldn't have to use it in every game released as I think it ruins some games.