INITIAL REVIEW: It definitely does the job, although you can't fit it to the top of doors (to wedge them open further than a few centimetres) as the stopper just gets squashed (due to the increased pressure and angle) - I had wanted to wedge the door open so that my son couldn't trap his fingers in the hinged side as well as the open side of the door, and this could only be achieved if you attached the stopper to the top of the door, which unfortunately didn't work.
That said, the manufacturer doesn't say you can use it in this way, or show any pictures of the stopper being used on the tops of doors, so I can't mark it down for this - it does what it says it should do, fits very snugly and is very sturdy.
What I have marked the item down for is the cost - it is basically a piece of dense foam, and as such the price is double what it probably should be ...............
UPDATE: 2 months on and I've downgraded the product to 1* as it has begun to split in the corners where the obvious pressure points are.