danielcaux, I am not sure what is so special about this band. A page or two back, you will see that I sometimes feel they sound like easy listening. BUT, I think for me, I appreciate that they were a "progressive" band as far back as 1967 (their first album), so the music can be kind of interesting for the time - a nice balance of instrumentation...and interesting themes/concepts, if you are in to that sort of thing.
I prefer Moody Blues to Pink Floyd though they're quite on the borderline of pop and rock. Certainly I've found them to be very consistently good over the '67-'72 period(I've missed a couple of their albums in that period). They have some of Floyd's depth, maybe Justin Hayward has a bit more charm than David Gilmour. Maybe that they have less of Floyd's cynicism and caution is a strong point. They could certainly be called pretentious, maybe more so than Floyd, but I think their overall result is better music.