I made two posts about it when I was desperate to find another way around SN. I didn't want to risk welfare checks and I only knew of DMC at the time. Now that I have got a domestic source for SN, I will most likely use it instead of MMQ.
Like the other people in this thread mentioned, there really is not a lot of studies done on its reliability and lethality. Most of the information you're gonna find is from the 80s-90s. However, there are a lot of anecdotal stories of people dying in drug related communities. And those people took relatively low doses.
So the method does not have a lot of evidence to support it. But I do personally believe that if taken with the right combination (lethal sedatives and benzodiazepines), it can kill you.
But my honest thoughts for myself? I'm using it as a back up plan. Yes I found a source that does not require you to be a company and will ship to residential addresses. But I rather take SN as there is way more research on it and evidence backing up the lethality.