I like the fact that the Nintendo games are so accessible to young people like my nieces and nephews so I can play with them but also have the hardcore gamer edge to satisfy me when I want to be challenged.
The gamepad offscreen play alone is worth the price of admission. Anyone that shares a TV in a household will love the fact that when your better half wants to watch her 'chick shows' the fun doesn't stop you just switch to offscreen mode and keep the party going. For this reason I was able to clock in 400 hours of Monster Hunter 3U.
There are so many good deals when it comes to the Wii U: I got Windwaker HD for free, I'm getting Bayonetta 1 for free today along with my purchase of Bayonetta 2, I'm buying new games disc and all for incredibly low prices. Everything is so affordable...
Also consider the 3DS to Wii U connectivity, that is pretty cool as well.
The Miiverse is kind of rad, I enjoy all of the comments and amazing artwork people come up with... Also Amazon prime streams quite well on my system compared to my Samsung smart TV
I have a pretty kickass gaming PC: i7 4770K, GTX770, 16gigs RAM, 27" 1440P monitor and it doesn't get nearly as much playtime
