As a launch date title, I am quite impressed with the quality of this game. So, lets start with the review.
Like almost all Mario games, the story starts with Bowser kidnapping Peach, and Mario and his “entourage” are thrown to another world. Once that opening is finished, the game starts. The levels look gorgeous in HD, and the muisic (like always) has that nice happy Mario tune. As you progress, like always, the levels get harder. But, the levels are not that hard until you get to the final word, which brings me to my first con. Some of these levels are just too easy. However, in NSLU, that is a totally different story. Anyways, one of the major pros of this game is the multiplayer.
Nothing like some good ol’ local multiplayer with friends or family.
For the multiplayer modes, it’s ok to work together to beat the level, but it is really to be that guy with the Gamepad, who just traps everyone in a giant wall of blocks. Another good thing about this game is the Miiverse integration. For example, it is nice to know that you beat the level in less than 50 seconds, or you beat the level without losing a life etc. And, you can post that with a comment to Miiverse.
I believe that Nintendo made quite a good use out of the Gamepad. For example, when playing with more than one person, one person can use the Gamepad’s touch screen and tap where they want to place blocks to help (or not) their friends. Also, you can play with the Gamepad alone, as well as just on it’s screen with off TV play.
Now, in NSLU, it is all the levels from NSMBU redesigned and re-engineered to fit Luigi’s unique abilities. He jumps higher, slides more, and just has a looser control. The difficulty of this NSLU is more than NSMBU, so I would recomend NSLU for the seasoned NSMBU veteran, because if you go to your local video game store, NSLU costs $29.99, but NSMBU costs $59.99. The average consumer will probably choose NSLU, because of its cheaper price. However, I would recommend buying NSMBU and then download NSLU/buy it at your preferred video game store.
So. to round up my review, NSMBU and NSLU are both great games, and I would recommend both, so here are my scores.
New Super Mario Bros U (By its self): 9.1
New Super Luigi U (By its self): 7.9
New Super Mario Bros U and New Super Luigi U (together): 9.7
Wii U Land 
I hope everyone enjoys the review. Please say your opinions in the comments, as I will use your ideas in my next review. Also, if the link does not work, here it is again: http://www.youtube.com/watch?v=lNYl1-8JHEQ (it is the intro to the story).