I'm considering one (or two). It usually gets down to -20F where I am and I need a way to heat a garage (2x S19k Pros isn't enough). At 140W and as low as $130 USD, seems like a good idea. Except that I am concerned about it's 'openness'. Looks like I'm getting a very locked down device. A literal "black box" in this case.
Is this the experience from most people? Does it lack a web UI, is it app controlled only? Does it phone home?
These are desktop heaters, good for warming your hands if your office is cold. They won't put out anywhere near enough to heat a -20 garage, especially if 2xS19k Pros aren't enough.
Think of the wattage in relation to a traditional electric heater - they may be 1500w, so a 140w device isn't going to get close to the same amount of heat.
They do have both a web interface and the mobile app to use. AFAIK it only communicates with whatever mining pool you configure, but you can access the logs to see what it does.