If anyone in your family appreciates Nintendo's franchises, the Switch is a must-get.
If it's primarily for your kids, you have to ask yourself whether they would appreciate games like Breath of the Wild, Smash Bros, or Mario Kart.
The PS4 is more versatile and is a system that can truly serve as your home entertainment hub. I've got a PS4 and Switch and enjoy them both.
Xbox was good during the 360 era, but they are struggling to find their footing. I'd give their recent 1st party studio acquisitions some time to pan out before buying one. I can name only 3 Xbox exclusives that might be worth playing, and that's Sea of Thieves, Cuphead, and Forza. Both Nintendo and Sony have many more exclusives that are worth playing more than the Xbox's 3, IMO.