I think quite highly of solar cookers. This one also happens to be cheap and easy to make plus very simple to store.

I have also been disappointed in a lot of designs because the sun simply does not get strong enough in the winter here.
Even at high noon during Canada's winter it is only about as strong as it is at dawn in the tropics.

Something a lot of people miss is how much more air the sun's rays go through when it is at a low angle and how much heat energy the extra air absorbs.
It is not just about the oblique angle covering more area on the ground with the same amount of light. The weakness of winter sun can't be completely compensated for by tilting the collector.

So Solar cooking here is pretty much a summer time thing.