I will say Nintendo.
Microsoft had a good opportunity to build more momentum for next-Gen while introducing Project Scarlett. There were some intriguing games presented in their conference, but the way they talked about Scarlett made me wonder...why couldn't they present that information the way Sony did? The 120fps, 8K stuff are find and dandy for tech people, but for me, its kinda just fluff. I guess showing Halo Infinite as a Scarlett launch title was cool, but it didn't really do much for me.
Ubisoft was alright..Though it did talk a lot about the Tom Clancy games and what not. Nothing really that interesting to me.
Square Enix's conference was actually pretty darn good, if mainly carried by the hype that is Final Fantasy VII remake. FFVIIR looks really promising. The production values of the game is pretty insane (the Midgar episode is on 2-Blu Ray discs?!?!). A lot of their other presented games were either not interesting or already shown previously that didn't present anything new or cool that moved me into looking more into those games. Avengers kinda dragged too long. It was cool seeing the voice cast, but there was very minimal gameplay in the presentation. I am sure there's more on the show floor and that the game will be fine, but at face value, the presentation didn't show how the game will work.
Nintendo did a really good job. It was unfortunate that Animal Crossing could not make it as a 2019 release, but it looks really promising. LM3 looks awesome. I was already sold on MUA3, FE: Three Houses, Astral Chain, DQXI, Link's Awakening Remake, Pokemon: Sw/Sh, etc. A lot of cool surprises from the third-party aspect as well (i.e., The Witcher 3, Alien Isolation, Trials of Mana Remake, Panzer Dragoon, No More Heroes 3, Contra, etc. The tease of a Breath of the Wild sequel really surprised me and I cannot wait for it. Finally, the two Smash Bros. Ultimate Fighter Packs 2 and 3 trailers really impressed me. While some of the rumors came into fruition, just seeing the gameplay and the references showed how much care the fighters are given for this pass.
Gotta say, I will give this year to Nintendo. Square Enix is second on my rankings..