Nintendo.

Almost no shooters but RPGs, platformer and party games, which is more fun. And Zelda sequel.

Yes right, I forgot to mention, Nintendo also had a bigger genre variety.

The one that announced a game I've been waiting for about 19 years, showed almost 30 minutes of pure, exciting gameplay with a crap ton of developement information and other details and gave an October 8th release date. That one won.

Sorry Nintendo. It's MS this year.

MS:

27 out of 30 announcements (90%) on the game pass day 1

Nintendo:

Skyward sword, single, fully priced remake (unlike Mario 3d all stars, where we've had 3 games for that price) 

Mario Party ... that shoud've been a DLC, but it's a $60 game.

Metroid 5 ... great, but again, it's $60!

These 3 games equate to 12 months Game Pass Ultimate with way over 100 games in its library. 

Since Elden Ring is the only game from the entire event that I would even remotely consider buying on release, I guess that means that for me FromSoftware/Bandai Namco "won" for me. Microsoft and Nintendo had probably the best conferences/showcases overall, but no game they showed has me nearly as excited as Elden Ring.

Why ?

It's a new entry after 3 years, it's hugely common for Nintendo consoles to have several Mario Party games. New game, new boards, remake of the best mini-games of the series, way more comprehensive than Super Mario Party, why should've been a DLC ?

That's a remaster, not a remake

To be fair, it's expensive even for a Nintendo remaster. Twilight Princess HD had bigger technical improvements and it costed 49,99. Not only that, but it had a limited edition with an amiibo and a CD Soundtrack for... you guessed it: 59,99.

Gamepass subscribers won E3. Joking aside, Nintendo had a solid showing but Microsoft having all those games available on gamepass day one is mind blowing. Very pleased I got a series s and Gamepass subscription.

Just to be real: the only contenders here are MS and Nintendo. Everyone else was disappointing, boring or outright terrible. Well I give some of the smaller ones the advantage of being funny like Devolver.

But looking at games and announcement only MS and Nintendo did a worthy show. Whoever wins depends on the person direct tastes in games I guess. Me personally Nintendo for SMT and Advance Wars.