My wife & I played this game for hours yesterday.... I really like it.
I don't know if calling it a Cooking Mama clone would be exactly right. In my opinion, I would say Order Up is better than C.M. in many ways.
Order does takes the Wii-mote food cooking aspect from C.M. (chopping, slicing, etc), but it takes it a step further by letting you purchase different types of restaurants (comfort food, italian, mexican, etc). You get received orders from the tables (ranging from 1 to 4 people), so unlike C.M, you can cook multiple meals at once. The faster you get the meals out, the bigger the tips, which gives you more $$$.
You can use the $$$ to hire helper chefs and upgrade your equipment. You can also buy secret recipes, and spices that you can add to your dishes during cooking to get bigger tips. The ultimate goal is to get each restaurant up to 5 star status. After your get 5 stars, a food critic comes, and you have to serve them perfect food to get a good review.
Also, every once in a while some rats will infest the kitchen, or the health inspector will stop by. These trigger a couple of mini-games. There is also a Delivery Guy who brings "fresh" ingrediants for the day. Any meals you sell that have the "fresh" ingrediant will get a bigger tip.
I would have been disappointed if Order Up had just straight up copied C.M. Overall, I am pleasantly surprised by how fun this game is, and I would recommend that folks give it a shot.