I would go to Yak & Yeti with your kids. Our DD12 and DS8 both loved Yak & Yeti on our trip in January. Try the fried green bean appetizer. Our kids LOVED it! It's a great way to get the kids to eat their veggies while on vacation.
DH and I ate at Jiko without them and thought it was a good place to go without the kids. We had so much food that we brought leftovers back to our room afterward and the kids did enjoy them. Actually, I never did see the rest of my steak because DD wolfed it down as soon as we walked in the door, even though we had fed them before we left.
From my experience, kids would enjoy the food at either place, but the atmosphere at Yak & Yeti is better overall for kids.