I don't own a wii u but my cousins do and I played Nintendo Land for hours. My favourite minigames are Luigi's Mansion and Mario chase. We had four remotes so that made it even better. I didn't play much of the others but I presume they are good too.
It's fun, but it really is more fun with others. I seem to lose interest in playing it that often because I have nobody to share my gameplay experiences with. In fact, I seem to lose interest in playing games or going back to them period due to me not having anyone to play with.