In the mid 2010s, the "battle" of Wii U versus PS Vita was on fire here in VG Chartz. While both systems clearly underperformed, both PS Vita and Wii U users where arguing about which console would "win" this war.

I still remember a lot of users arguing that the PS Vita had much better sales in Japan, so that could've helped it to outsell Nintendo's hardware. But if we look at the scenery around the world, the Wii U always looked more popular than the Vita, mostly due to Nintendo's success with games like Super Mario 3D World, Splatoon, Xenoblade Chronicles X, etc.

VG Chartz has PS Vita at 13.13 million, while the Wii U is sitting at 13.56 million, but are those official numbers?

So... Who won this epic battle after all?

They both lost

I remember thinking both were underperforming but would still do 30-40 million lifetime. Haha.

Whoever won, they lost.

This is kinda like asking who won out of Germany and Japan in WW2.
Whichever one managed to eke out a sales lead, both failed disastrously.

I have to say Wii U "won" even if Vita's reported figures by some sources hit over 15 million units.
Wii U had some iconic titles like Super Mario 3D World, Mario Kart 8, and The Legend of Zelda: Breath of the Wild (cross-gen, but still).
What exclusives did Vita have from any publisher that competes with that?
Sony abandoned the handheld space because of Vita. Nintendo went hybrid with Switch and some of Wii U is in the DNA. Admittedly, Nintendo has never made another piece of hardware that's a home console only (not even any versions of Switch or Switch 2) after Wii U which is significant.
Both lost pretty thoroughly. Wii U was annihilated by Sony and Microsoft, and 3DS destroyed Vita as well.

Wii U numbers are official .. Vita's are not. Here is some data, based on VGChartz, if it will make the choice easier for some .. 

As for this battle, one famous quote from my country is well suited:

"Não acho que quem ganhar ou quem perder... Nem quem ganhar nem perder, vai ganhar ou perder. Vai todo mundo perder."

Vita was quite successful in JP, though utterly bombed in every other region. Units were still being shipped oot through 2022, in fact. So from the perspective of legs and regional strength, Vita definitely edges ahead of Wii U.

However… by virtually every other metric (e.g. first-party success… I mean MarioKart 8 sold around a 60-70% attach rate, third-party support, annual average sales, success outside of JP, overall WW sales), Wii U wins.

Yeah, I think this nails it. I’m a proud owner of both systems, so I don’t like to dunk on either of them, but I feel like Vita is the “loser” here. WiiU, for all its failures, gave us a handful of the best games ever made. And several series or sub-series that debuted on WiiU — namely Splatoon, Super Mario Maker, and Hyrule Warriors — continue to be successful. Also, the system’s DNA endures in the Switch family.

The Vita, conversely, was a technological dead end for Sony. And while the system supported a ton of indie games and some very interesting AA Japanese games, its library was largely devoid of game-of-the-year contenders.