We have one in the garden which gets fed with household waste like vegetable peelings and used teabags. It also gets garden waste like weeds and grass clippings. The contents need stirring at least every 4 months (3 months is better). The mix tends to be quite wet so the cone is best stood on a dry spot in the garden.
The compost needs about 6 months to mature. In Summer, the mix gets warm but I am not sure it is hot enough to sterilise weed seeds etc.
One problem is that the cone or its contents attracts rats. I am not sure if it is the food value of what's inside or the shelter it provides. So it is best stood away from the house and anywhere that potential rat food is stored (sheds etc.) and on a solid concrete base like a large paving slab.
Overall, it is a neat tidy way of making a small quantity of compost but a big wooden bin would heat up better and hold more. So if you have lots of waste to process I would recommend that alternative. The cone here provides enough space for two of us and a modest garden only.
NN