Twin 2 1/2 year olds are loving the heck out of this.  It's easily pushable by one of them while the other rides.  At 2 1/2 they probably aren't quite strong enough to consistently self-motor but I can see it coming soon.  I would say the box states through 5 years old, but I can't see a 5 year old fitting in it that well or having much fun in it.  Should last till 4 or so though.  Solid plastic construction.  Instructions on assembly are about as good as you expect instructions to be.  The only odd thing to me was the packaging - sometimes parts you needed for one step would be spread through 3 different bags.  But fit it together fairly quickly even with having the twins "help" and we were rolling up and down the driveway in no time at all!