Well, for the Switch it depends on whether or not the games are actually coming in 2018. If Bayonetta 3, Metroid Prime 4, Pokemon, Shin Megami Tensei V and Fire Emblem all come I'd choose that, but none of those have concrete release periods.

From what we know Sony > MS > Nintendo

If Lost Soul Aside comes out next year, then PS4.

PS4.

PS4, not even considering VR, yet.

PS4 even without all the VR games I want.

It's hard to say since we know so little about the Switch 2018 lineup, as of now we only know that Kirby, Yoshi, Fire Emblem, Travis Strikes Again and Octopath are coming next year, if some of the announced but not shown games like MP4 or Pokémon did come out in 2018 then it'd give them a big push, plus there have to be more game to be announced...

PS4 of course, Gof of War, Spider-Man, Detroit and Shadow of the Colossus Remake are all day one for me

Come on, who voted Xbox One ?

And if Game Freak announces Pokémon for 2018, then the Switch will win "the game"

Well we still dont know almost nothing about Switch 2018. linuep and Nintendo yet need to start reveling Switch 2018. linuep, january Direct will be good start but even than they will not reveal full 2018. lineup.