The oil filled ones are safest all around, as nothing can come into direct contact with the heating element. Personally these are the only ones I would leave on at night.
The fan heaters are not so safe, and any heater where you can see a hot element is the biggest fire risk.
This topic has been covered in several threads. A quick search will help you.
The consensus is that these schools are actually much of a muchness.
If you are already in Kunming, find one that is convenient to travel to from where you live.
If you are not already in Kunming, find one that fits your visa needs, and is in a location you would wish to live in.
A reasonable choice of lumber that has improved over time. Fancy hardwoods like walnut, and mahogany are in abundance. There are some plywood and rubber-wood boards available. There are also some kiln dried imported softwoods and merbao available. Some of the lumber is very green, so look for the kiln dried if you need stable timbers.
Echo everything said by others.
Breakfast great and the serve from 8am. Most other places say 9am and they still are not ready.
Sandwiches are cheap 22-32, and really packed full of filling. We got some sandwiches for a day out, the only mistake I made was ordering two, as this was too much. These are seriously good sangars, and they are wrapped in alu foil.
In fairness to Metro, they are a wholesalers, and not really a supermarket. Hence the need for a card, which can be got around.
They have improved in the year I have been away. They now carry a more consistent range of imported foodstuffs and they also seem to have sorted out the mported milk supply.
They have a wider range of electrical appliances now, there is a coice of more than one toast. There is also a better range of seasonal non foods, like clothes, shoes, garden furniture and camping gear.