I have one (came with the system). It works great, but nearly doubles the weight of the set-up. Instead, I use a plastic cup that I got at a fair. For me at least (Caldera Cone with a Snow Peak 700 mug) its just about perfect.
To pack up my kitchen, I first put the stove in the bottom of the pot and then set the fuel bottle on top. Next I coil the Cone enough the get it in the pot, push it down until it contacts the bottom, then let it unroll so it pushes against the sides of the pot. I then place the rest of my kitchen (spork, foil lid, and lighter) into the center of the cone. Finally I invert the cup and place it over the exposed part of the Cone. It slides down into the mug and is kept in place by the force of the slightly unrolled Cone. (I hope the description is clear, I can post pictures if its not).
It works great for me, plus the cup is about 1/3 the weight of the Caddy and still retains the beverage container capability. I would encourage you to scour your home or the store for a lighter alternative before you buy the Caddy.
Adam