They are currently offering these in Florida and Ohio but I just custom-ordered one at my local McDonald's. It ended up costing me $2 ($1 for the chicken patty and $1 for the McGriddle cakes).
Of course, given the nature of custom ordering, I ended up with a McChicken with McGriddles cakes instead of a bun rather than a McChicken patty and two McGriddles cakes, as was shown on the order screen:
The idea here is to offer chicken and waffles in a convenient, portable form. It works insofar as the portability goes.
The McChicken patty was decently crispy with a nice, peppery flavor and heat on its own but didn't hold up well to the spongy and maple sweet McGriddles cakes.
Nutritional Info - McDonald's Chicken McGriddles
Calories - 390 (from Fat - 130)
Fat - 15g (Saturated Fat - 4.5g)
Sodium - 1000mg
Carbs - 51g (Sugar - 14g)
Protein - 14g