The go-kart racing was so choppy it was almost impossible to play, the handling of the karts made me wonder if the tracks where made out of ice covered in butter.
The soccer game was brutally boring, to kick the ball you use the touch screen and slide your finger. It felt like I was playing a free iPhone app. The saving mechanism was even worse, having to switch from the Game Pad to the Wiimote every minute was annoying. To save the ball you had to swing the Wiimote in the direction the ball was going. My "goalie" never went where I wanted them to.
The American Football game was by far the most frustrating. It took forever, once again switching from the Game Pad to the Wiimote every 5 minutes this time. I don't know what to say about this, it was boring.
Golf and tennis were a little better, although they were not on par (no pun intended) with the Wii Sports versions.
I didn't bother playing any other sports after being fed up with the most annoying thing about the game. No pause menus while playing sports. Yup, you heard me. No way to quit the terrible sport you were currently playing, no way to pause if you needed to do something else for a couple seconds. You have to go back to the Wii U main menu and restart the game.
So should you buy this game? It depends, if you like spending $64 on complete crap, then yes go right ahead.