My (rather large) two year old loves Monsters Inc.  He is wearing size 4T now, but his clothes are starting to pinch, so he's almost in a size 5.  I can't imagine this fitting him when he's in a 6.  It's pretty easy to get on, but getting it off is pretty stressful.  It has to go on over his head with his hands up in the air.  There is a small piece of velcro at the back of the neck, but it doesn't stay closed at all.  I may add a drawstring.  One of the biggest design flaws is in the bottom, where his legs go through.  Elastic would be a great improvement.  It fits my son right in the perfect spot so his legs move easily, but if he was just a few inches shorter I think it would be cumbersome.

It is made of thin foam, maybe a centimeter thick.  I'm sure it will last the night, but I seriously doubt it's ability to be handed down.  I may be pleasantly surprised, but I'm not holding my breath.  The shoe covers will probably require a bit of two-sided tape.  My son wears a size 11 shoe, and they fit perfectly over his loafers.  If his shoes were much smaller, I think they would probably spin around as he walked.