What really pushed me into getting this, is that aside from the Nunchuk, it also came with a Wii U Sensor Bar. I know I already have one (actually two), but there's no harm in having an extra for you-never-know! I say "Wii U Sensor Bar" because there's a slight difference from the one that came with the Wii. There are no real or major differences as far as I can tell, except for the color. The Wii Sensor Bar has a black and grey/silver color combination, while the Wii U Sensor Bar is all black. Even the LED color is the same for both.
I actually have 3 Sensor Bars now. The one from the Wii, the one from the Wii U, and the one from the Tsuika Pack. May become 4 after I get my Wii Mini. O_O