I got one for Christmas and had my first suggess with it yesterday. Beef Daube - stewing steak marinaded in wine overnight and cooked for 5 hours with carrots and onions, then peas and pasta added for another 30 min. Truly one pot meal and no browning required first. It was excellent and just what I was hoping for from a low cooker. No effort and hardly any washing up!
But does it really save much energy? What difference is there between having the oven on low for 2 hours and the slow cooker on high for 5.5 hours? What about a bolognaise type thing, where I can make it by simmering gently on the hob for about 45mins, but slow cooker would need to be on for several hours?