^Methadone is a it of a conundrum though. It's a powerful MOR agonist, like all of our other favorites, Heroin, Morphine and so on. It's been noted to cause an ever so slightly higher rate of respiratory depression compared to other drugs in the class, but not enough to actually call the drug more dangerous than other Opioids. I really think that this is conjecture at this point though.
The conundrum of Methadone is such that I feel it kills in a different way than a lot of other Opioids. As almost all drugs are digested and metabolized instantly (30-45 minutes), a novice has every reason to suspect that Methadone will come on just like an Oxycodone or an Adderall. You can imagine that a lot of folks are going to think they underdosed when they're not high at all an hour and a half later. Then, they consume more Methadone and slowly stop breathing.
The fact that Methadone comes on so slowly makes it quite difficult to actually detect that you're going under. You'll just slowly reduce your respiratory rate over the course of several hours until death. This, is in my opinion, the most dangerous characteristic of Methadone. The fact that maintenance dosages in the USA routinely reach 150mg per day doesn't help the situation either. There's enough drug in one of those bottles to kill the right person three times over and it's less liquid than a shot at the bar.
As far as Methadone being inherently more dangerous than other Opioids, I don't see it. I think it's more of a circumstantial issue. If you're well informed, it shouldn't be a problem.