Even DEEP PURPLE were considered a "progressive rock band" back 1970-71 I recall.
By and large prog rock acts maybe technically of a high musical standard but overall are mostly boring to listen to the exception being FOCUS from the 1970s & EMERSON LAKE & PALMER also from the 1970s (except maybe there Love Beach album?). Many rate GENIUS which is fair enough although I can't say they ever captured my interest musically, I tired listening to some Steve Hackett solo albums a few months ago and decided to bin them!!.
E-Z
LOL. I remember being coerced in to listening to Focus III in my mates loft when I was a lad back in the early 70s - I was about 12 years old. It was a bit too deep for me at the time and I've never given it another chance since then so maybe I will sometime but I don't know about all that yodelling....
Personally I like Genesis (I assume 'GENIUS' is a typo..??) up to and including "Duke" but after that they just turned crap.
Hackett is also well past his sell by date these days and hasn't produced a decent album since "Defector" in 1980. "Spectral Mornings" was a good one of his although some of the sound production was a bit dodgy on it..."Please don't Touch" was a good one too with better production than " Spectral Mornings" and a couple of good guest vocalists in Randy Crawford and the guy from Kansas. Worth a listen.
Could never stand anything ELP ever did meself....
All a matter of personal taste lad - all a matter of personal taste..