Just bought this off the shelf at REI. The thing is no joke: it boils a liter of water in a minute (my estimate, didn't actually use a stopwatch) or so. Insanely fast.
I bought this basically as a "weekender" stove for snowy ascents -- think Shasta/Casaval Ridge in February, or Rainier/Ptarmigan Ridge in June. The JetBoil is just too small to shovel snow in, and the Reactor's 1.7-liter pot is wide enough to take in big clumps of snow.
I had planned to use this inside my tent with a hanging system, but given the manufacturer's repeated insistence about carbon monoxide (which you can't smell), I guess I'll have to use it outside, which is kind of a bummer. Still, at least I can take comfort knowing that I won't be freezing my ass off for a half-hour at a time brewing up -- I expect this thing to churn out liter after liter. I wish it were still cold and snowy enough that I could give it an alpine test. But so far, it passes the threshold garage test.