Hanna got a John Deere Ride On Gator for her birthday last year. She is loving it. She rides it all the time (when it's charged up). She has helped me bring compost to the garden, grab hay from the barn with it, and crate weeds from the garden to the burn pile. It's actually quite handy and a great way to get more outside play time.
Whenever a friend comes over that's the first thing she wants to show them, and she takes them for a ride all around the property (if she can get them to let her drive ~ with the boys the answer is usually not).
It's a little pricey, but I'd say for the time spent on it and the fun had it paid for itself.