Switch > PS4 > XB1
Although hype for Dreams, GOW, Monster Hunter Bundle and the release of SOTC is this month, I do not think it will be nearly enough to push PS4 numbers above those of the Switch. Next month will be a really interesting and telling month. IF the Switch can hold next month then we'll get a much clearer picture of how the rest of the year is going to play out. I still think both the PS4 and the Switch are going to continue exchanging the lead (in the US of course).
The PS5 Exists.