First off, no... this isn't a Volcano Taco. I've seen a lot of people say that this is the same thing, when they're not at all, besides the color of the shell. The Volcano Taco is a regular crunchy taco with a red shell, and Volcano sauce. The Fiery DLT is a spicy shell without any sauce. Now that THAT'S cleared up...
Again, I'm not impressed. As usual, the flavor of the shell is really minor and not worth the extra price over a regular shell. For this one, the flavor of the shell is actually reasonably spicy, and has a sort of tangy flavor as well from the lime flavoring that they put in it. It tastes pretty good, but the Taco Bell "beef", as always, overpowers it. I don't normally care for sour cream IN things, but I like it ON things (warm sour cream disgusts me). Having a DLT without it being supreme is something I wouldn't bother with, because otherwise it's just salty as hell, to me.
The Fiery DLT is fine, but it's not worth the price. I think I'd rank it behind the Nacho Cheese, which I wasn't expecting, because I tend to really like spicy things. The Nacho Cheese DLT just has more flavor, I think. It's decent, it's okay, it's alright... but I want the beefy crunch burrito back and permanent.