Wii for me. More games, better games, plus (IMO):-

Wii party >>>>>>>>>>>>>>>>>>>>> Wii party U
Smooth moves >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Game & Wario
Mario kart Wii > MK8. (As i said, imo, don't kill me!)
Wii Sports, Excite truck. Wii u didn't have anything like these games.

I would go for the Wii.
Bulk of the good Wii U games ended up/ending up on the Switch.

WII. It has some of my favorite games of all time.

Wii U has some great games too, but not as much as the Wii.

Yeah I'm gonna go with the Wii as well.

Both systems had some amazing first party gems, but while the Wii U had horrendous droughts in between them, Wii generally managed to plug the gaps will cool additions like Monster Hunter Tri, Goldeneye 007, Silent Hill Shattered Memories, de Blob 1 & 2, No More Heroes 1 & 2, Red Steel 2, Rayman Origins, Sonic All Star Racing & Colours, etc.

Also, where the Wii U Gamepad was cumbersome and ultimately didn't add much, the Wiimote + Nunchuk were a revelation when properly utilized. Playing Wii Sports Resort with 1:1 motion controls in 2009 felt downright futuristic, like something off Star Trek, while pointer aiming blew analogue sticks out of the water.

Enjoyed Wii U more than is thought possible by the mainstream. A huge chunk of my life flew by and I hadn’t paid any attention. I dove into the game pad way too hard for my own good.

I am amazed 25 people voted Wii U :o
Wii with out a doubt had almost every category going better for it other than graphics and portability

Eh, when we talking about games, Wii U had far better and actually of best Mario Kart games ever, also Pikmin 3 is best Pikmin game, DKTF is far better DK game than DKCR, same goes for Smash Bros 4, NSMBU is better than NSMB Wii, not to mention Zelda BotW...also some games like Splatoon, Mario Maker and Yoshi Wolly World that Wii didnt had. Wii had much bigger lineup of games, but even Wii U had much smaller lineup of games it was very high quality. I cant speak for others but for me personally Wii was disappointment and I enjoyed Wii U much more than I did with Wii, only MK8, Splatoon and Zelda BotW for me are better games than anything Wii had.

Yeah, well, you know, that's just, like, your opinion, man. - TBL 
:p

Virtually the same thing happened after the Gamecube era. Despite it being a horrible failure with significant droughts and games that didn't fit well on the console, there are still those that fanatically try to pretend it was some sort of golden age for Nintendo - though the reality is that it was a dark age.

Never under-estimate that contrarian contingent of us Nintendo fans to pretend like the company's biggest misses were awesome and the biggest successes were garbage.