Controversial opinions on metal

DT, probably. The Crue are fucking washed up.
Great band, though.

I wasn't asking what band was more popular here, but in general. Crüe has sold over 80 million albums, according to Wikipedia, while Dream Theater has sold 8 million, so you're obviously wrong.
 
If there is a difference, then it is exclusively concerning metal. There is no difference between prog rock and progressive rock.
 
Because "progressive metal" has come to, ironically, mean something pretty archetypal by now. Cleanly produced metal with crystal sound quality, time changes and complex phrasing, usually clean soaring vocals and a less "driving"/"galloping" sound to differentiate it from power metal (along with the fact that is is more structurally complex, etc.). Truly "progressive" metal is not "progressive metal" at all according to genre definitions because something that truly progresses metal, or music at all, can't really be confined to a genre. Usually, bands that ACTUALLY progress things are considered "avant-garde."
 
Because "progressive metal" has come to, ironically, mean something pretty archetypal by now. Cleanly produced metal with crystal sound quality, time changes and complex phrasing, usually clean soaring vocals and a less "driving"/"galloping" sound to differentiate it from power metal (along with the fact that is is more structurally complex, etc.). Truly "progressive" metal is not "progressive metal" at all according to genre definitions because something that truly progresses metal, or music at all, can't really be confined to a genre. Usually, bands that ACTUALLY progress things are considered "avant-garde."

(edit: I wrote my response before you added the second half of your post, so by now I probably sound like I'm just repeating what you said)

Point taken. It does kind of seem like 90% of bands labeled "progressive metal" are really just emulating the Dream Theater sound. But I don't see how that would necessitate giving those bands a label separate from "progressive". If anything, they're just pseudo-progressive metal.

It's not just in metal that you find pseudo-progressive bands imitating progressive ones, though. I've heard people make the same distinction among classic rock bands. There are groups like King Crimson, Pink Floyd and Gentle Giant, which actually progressed rock music, and then bands like The Moody Blues, Kansas, Camel and Rush who are called progressive but were really just relying on complexity and/or an artsy sound, rather than actually inventing anything.

I'd say that pseudo-progressiveness is something that's always going be mistaken for true progressiveness, and since you can't really have a genre without imitator bands, you might as well be calling the imitators "progressive" as well if you want to be able to have any discussion of progressive music as a genre.
 
Actually, Camel were pretty heavy imitators of King Crimson. Though I guess you could call them prog if you consider it progressive to mix KC's sound with jazz rock. Of course, KC already covered that territory with "21st Century Schizoid Man", so maybe not.
 
Because "progressive metal" has come to, ironically, mean something pretty archetypal by now. Cleanly produced metal with crystal sound quality, time changes and complex phrasing, usually clean soaring vocals and a less "driving"/"galloping" sound to differentiate it from power metal (along with the fact that is is more structurally complex, etc.). Truly "progressive" metal is not "progressive metal" at all according to genre definitions because something that truly progresses metal, or music at all, can't really be confined to a genre. Usually, bands that ACTUALLY progress things are considered "avant-garde."

Pretty much. If every band classified as progressive metal (since there are shit ton) was actually significantly innovative, metal would surely be a LOT more diverse than it already is. Granted, even as valid genre its boundaries are less rigid than other genres, and some bands labeled as such don't really fit the Dream Theater rip-off mold at all, but the nomenclature is still fairly arbitrary and meaningless as an indicator of how unique the music actually is. Then of course, there are bands like Isis and Pelican who are arguably just as innovative but are called post-metal because they still helped shape a distinct sound.