Whether or not the iPhone XS is worth it, really depends on what you want to use your phone for. If you want to upgrade from an older model and experience some of the more contemporary iPhone features but not break the bank, the iPhone XS could be perfect for that.
This makes an absolutely awesome entry level iPhone, especially if you’re looking for a smartphone for one of the kids that’s a bit older. If you’re willing to pay just a bit more for a phone that’s more powerful with a broad range of color options, you could also look at the iPhone 11.
If price is your top priority some of the older models could still do the trick for you. Overall the iPhone XS has a powerful A12 chip with good performance. The value for the cost makes a refurbished iPhone XS a great choice.