It really depends on if you plan to buy the Switch or the Scorpio at launch.But assuming that you wont buy them at launch, and since you got a PS4 already, go for Wii U.Its library is simply amazing, and will keep you busy for more than 1 year(depending on how much free time you jhave)
My (locked) thread about how difficulty should be a decision for the developers, not the gamers.
https://gamrconnect.vgchartz.com/thread.php?id=241866&page=1