Gotta say, imo, Nintendo stole the show in terms of games. That's mainly because I gave a crap about every single game that was showed off. Smash Bros, Hyrule Warriors, Splatoon, Yoshi's Wooly World, Mario Maker, even Captain Toad's Treasure Thunker looked interesting to me! And yes, NEW FREAKING STAR FOX!!!!!!
And of course, Super Smash Bros.! With the 3DS Version and The iDOLM@STER Movie, October is looking mighty attractive!

Also, it was amazing to see Palutena even though I totally saw it coming and I actually like how the Miis were integrated into the core game despite being against the idea at first.
Microsoft had a pretty good conference mainly because they focused on nothing but games, games, games! Its a HUGE improvement from the disaster that was last year, though I'm still not interested in the Xbox One as of yet, though the Halo Master Chief Collection and Sunset Overdrive are cutting it pretty close to convincing me.
Sony, honestly, had the weakest, but it was still fantastic! It was amazing to see Batman Arkham Knight and Mortal Kombat X gameplay during the show and more than made up for the absences of developers such as Square Enix and Namco Bandai! Yes, I was slightly expecting a One for All Western release announcement. The only reason I say Sony had the weakest was because the middle portion that talked about Playstation TV, Playstation Now, and the new show called "Powers" was kinda boring, but the end made up for it.
Overall, a nice E3 this year overall in terms of the big three.