Its a stove. The only difference is it has one big hole instead of a bunch of little ones. It uses heat transferred back to the cup to heat and boil the fuel. It might appear simplistic, but that is its elegance. What is really going on is as complex as in any other stove.
It also works very well with small pots. And is super easy to fill, light, no priming needed to aggravate you, easy to monitor fuel level during burn, super easy to simmer, super easy to snuff out. Super easy to make and super cheap to boot. Oh yeah, its super light. Cup, windscreen, and wire fabric support weigh 1.03 oz, and fit in the pot with oodles of room to spare.
Yeah I know, its heavy. But the windscreen is about .6 oz of that, I went overboard on it.
It is an A++ in the world of stoves for small pots to me.
I re-did boil tests in my kitchen with the Klean strip Green denatured alcohol. This is ~95% ethanol, ~5% methanol, trace other crud. Wow, it heats. I did the math and figured it would be at least 11% better than the SLX, and it was . It cut boil time for a full, vigorous rolling boil to 8:15 for 2 cups starting at 71F. On 0.5 oz it boiled for additional 2 min without restricting to a simmer. That would provide enough extra for it to work outside, or with cooler water on 0.5 oz .
The downside is that the Klean strip Green DOES SOOT THE POT a bit. Even a small amt of varnish looking buildup on pot bottom. Might be tolerable, my calcs say it has even ~5% more heat value than everclear. (the 5% water in everclear has no heat value and a high latent heat and sensible heat capacity)