Poking around it seems diet soda is linked to increases in the chance of diabetes, high blood pressure, INCREASED weight gain, osteoporosis (same as regular soda), higher cholesterol, and it has no nutritional value. You tend to consume less water via diet soda. So you are getting less bang for your buck so to speak as opposed to just drinking water.
In some cases it has the exact same problems as regular soda. While most folks think it's better for them. So they may make worse choices in other areas because the diet soda is OK. Supersize that combo because I'm getting a diet soda! So there are both actual issues with the soda and some choice issues with folks that drink it.
FWIW, I have drank Sundrop since I can remember. I drank a lot when I was a kid. Before the diet I had cut to one a day. One of the reasons I dropped weight as fast as I did initially was cutting soda out completely. I'll have a sip of my kids Sprite occasional, and drank a little gatorade the other day; but they taste like cough syrup to me anymore. About the only thing I can tolerate is sweet tea, and I only get that if we go out to eat. I don't even bother to make it at home, and have not in probably a year. If I want to sweeten my coffee up I put vanilla latte protein powder in it, vanilla hazelnut MCT oil, or both.
The MIO I use in my water at work has sucralose in it. If I could find a better option I would probably try it. But it's got far less sugar and carbs than the gatorade I used to drink. I've looked into making my own, but most have a lot of sugar in them.
Why do you let your kids have Sprite? You're leading them down the path to obesity.