Does your kid need access to the internet at all times? Do they need a camera available at all times? Are there a lot of apps that they need to have available to them? If not then probably a flip phone would be a better choice. Either that or one of those kids smart watches like a Gizmo if you want something you can track their location with.
Remember the main purpose of a smartphone is to be online all the time, and children are geniuses at figuring out how to access things that are supposedly blocked or restricted