If you like the exclusives and have the money then there is no harm to be honest. Personally, i wouldn't get both X1 and PS4 as i'm not so keen on Microsoft's exclusives. Wii U and PS4 will do for me.
Also, i wouldn't recommend both X1 and PS4 if you were into multiplayer alot due to the subscriptions.
Xbox One, PS4 and Switch (+ Many Retro Consoles)
'When the people are being beaten with a stick, they are not much happier if it is called the people's stick'- Mikhail Bakunin
Prediction: Switch will sell better than Wii U Lifetime Sales by Jan 1st 2018