Switch for Nintendo games and just about every indie or Japanese AA game, as I love the option to take the game on the go.
PS4 for Sony games, exclusives, and any multiplatform 2D fighters.
Xbox for multiplatform games (minus 2D fighters) since I prefer the controller and have a Gold subscription.
3DS for exclusives.
Vita for exclusives or low-tech PS-family exclusives, e.g., Iconoclasts, as I'd rather not be tethered to the TV if the technology required is pretty much the same.