The two are quite distinct. One really makes you feel the whole “capsaicin activating the heat-sensing nerves, making you perceive regular mouth temperature as burning hot”-thing, while the other just feels like a chemical burn from something dissolving the tissues in your mouth.
I bought [this mango/habanero sauce from a Swedish company](https://cdn.shopify.com/s/files/1/0119/0199/3024/products/image_50bcf47f-8e88-4a14-8409-d5cf9695d356_700x700.png?v=1568629966) the other day, and it’s 100% chemical burn feeling. There’s no sensation of *heat* at all, it’s just pain (and amazing flavor, once the pain from the couple of dashes I tried died down it left this very long lasting, lingering habanero flavor in my mouth). Some other hot sauces have this as well, Da Bomb comes to mind.
What gives? Capsaicin is capsaicin, right? The only thing that should matter is how much of it there is..right? How come some chili creates the pleasant heat that builds up until it burns and keeps feeling hot while others are just shades of hateful, aggressive pain, regardless of magnitude?