Appropriate age for Mindstorms

One student in RfG mentioned to me that she had a 4 1/2 year old grandson who might have fun with the Mindstorms kit.  I said I thought the kit was a little advanced for that age kid.  I suggested a couple of possibilities:

1. LEGO has a product line called WeDo Robotics, which is intended for younger children.  It's a little pricey, but many of the best LEGO products are pricey.  http://www.legoeducation.com/

2. As a parent-child activity, Mindstorms might be surprising, even though the child is young.  My grandson is 4 1/2 too, and he and his dad and I built a robot arm last week.  Ben has tiny fingers and is good at handling small parts, so he had an important part in the project.  Now he is expert at operating the 5-joint manipulator arm, and is proud to show it off.  The product is called the OWI Edge Robot Arm.  Ben also likes to work with me on Mindstorms constructions.