Product review (3 stars): Great Idea... but beware for existing installations
This is a great idea, so I purchased one for my recent kitchen renovation.  Only one problem: it doesn't fit the standard 24" dishwasher bay!  I have to assume that the company feels there are enough dishwashers out there which legs would not fit into the confines of the side elevations, but mine would have.  I contemplated reducing the width by hand with a file or Dremel.  But I'm not sure the brittle plastic would have handled this well.  Besides, this is one of those preventive measures that is a good idea if you can just slap it down, but becomes questionable if you have to make a career change to install it.

I would make several suggestions to the manufacturer.  For one, make a tray that fits in a 24" bay for existing dishwasher installations.  I think you would sell a lot of these.  Or, second, make it out of a more flexible plastic that could easily be cut down.

If this is a new installation and you can increase the width of the bay by 1/4" or so, I think it's a fine idea.