We (Two other geriatrics & myself) humped into Crescent Lake, and I took the Volcano stove for a test run. My experience is that it works, works quickly to boil water.
BUT......It is really a kind'of disposable stove. The Cup worked perfect, the water jug worked perfect. The stove worked very well however the stove is frail, the top was bent well out of round when it cooled, and as nearly everyone say's, it is a bugger to feed fuel into. But in fairness it does work.
I am going to build a much stouter stove out of electrical conduit pipe. I only paid $10.00 each for two of the swiss volcano stoves. And even if they only lasted for ten uses, it is a good deal.
They are tippy so I had to support the stove with rocks. Note: this was a field test, not a dry run in the back yard. Your mileage may vary.