I believe that you would be happier with the Switch over the Wii U mostly for the Switch's library potential as well as it's solid hits so far. With Zelda: Breath of the Wild, Super Mario Odyssey, Mario Kart 8 Deluxe for the major first party stuff as well as Minecraft & Rocket League with cross-platform multiplayer support (with PC & XBox One players... Sony is being overprotective with their players, refusing to do cross-platform multiplayer) as well as the ability to take it on the road with you (if you like), so you're not bound to a TV.
The with the Wii U, while it's more affordable, the game library is pretty much set (with only a handful to potentially new releases) & major stores are no longer stocking the system (in favor of the Switch)... so you'll likely have to hit Gamestop or secondary markets to get one. The system does have some great hits, but you will need to play with the TV as not all games support off-TV play with the Gamepad & some of the online features have been discontinued (like TVii & Miiverse are gone... so the Wara Wara plaza will be fairly quiet). The Wii U will likely have online support for a few more years, but it's going to be very sketchy beyond 2020.
While the choice is ultimately up to you, I hope this sheds some light on your choice.