It consumes 27W in warming mode and 619W in cooking mode.
I also have a 4 year old Crockpot slow cooker (8 "quart" IIRC) which consumes 47W in warm, 160W in low and 206W in high.
Edit: I just made something as substantially similar as their chicken & rice dish as I could and it also took 45 minutes and 0.4kWh. That works out at 5c in electricity costs (or 9c when taking into account my California marginal kWh costs). Not counted are the costs in water and electricity to wash the container after use which are pretty negligible as it is non-stick and just needs a mild clean/wipe. I can also confirm that power use did not change during the whole cooking process.
Since the temperature of the water bathing the meat (or veggie, etc) is a constant, you know exactly when your steak is a perfect medium rare. Not only is it cooked perfectly, the fats and marinade and etc are all sealed (quite literally) with the meat so the food is chock-full of flavor.