Should I get the Nintendo Wii U or Nintendo Switch?

It really depends on what you are looking for. The Nintendo Switch is a brand new Nintendo system that has been released on March 3rd, 2017 with a few games at launch, including Zelda Breath of the Wild. Though it is still really early in its life, there are a lot of new games announced for it including Mario Kart 8 Deluxe, Splatoon 2, Xenoblade Chronicles 2 and Super Mario Odyssey. However these games are not yet released so you will have to wait for a bit before playing these games.

On the other hand, the Wii U has been discontinued and Zelda Breath of the Wild is likely the last game Nintendo will be developing for the Wii U. There are already a lot of good titles including, 3D World, New Super Mario Bros U, Mario Maker, Mario Kart 8, HD Zeldas, Pikmin, Smash Bros, Splatoon, Xenoblade X, Yoshi, Kirby and others. So if these games are interesting enough, it may be worth getting a Wii U for.