All I can state with first hand knowledge is what I have experienced as stated above. I couldn't tell you what the limitations are below 0º, nor would I be out there in these temps intentionally. Would you really venture out in that type of weather and plan on using an alcohol stove? I hope not. In our case we had both, but ironically, it was the alcohol that worked in this unusual cold front moving through the area.
By the way, we have a trip planned for the first weekend in December and I will be taking only my alcohol stove based on last January's experience. I don't expect temps below 30º, possibly down to 25º, unless again, an unusually severe cold front comes through. If I run into trouble will be buming hot water off of my buddies if they happen to have the type of stove that will operate in those temps. However, based on my experience, my Pepsi and V8 can stoves will do the job down to 0º.