Saying that Haken has made ANY album-even Aquarius, which I love-that is better than the murderer's row of albums that were mentioned in this thread from other prog bands might be the single biggest bit of hyperbole I've read since the Terrrorizer review that said an album by death metal band Mithras was the greatest album produced in the history of music from the UK. Seriously, guys, lighten up a bit. Even Haken would find that notion silly.
I agree that Haken would probably find the notion silly, but that's just because those are probably their influences and it would feel weird for an artist to look at his own creation and say: Yeah, that's better than all those things that inspired me, I'm a freaking genius.
But I don't think this means that we, the people who have listened to The Mountain and those other albums, need to share those opinions. I am willing to say that those classics were, when they were released, a much bigger deal than The Mountain is now. But I think people often confuse historical importance with how good the actual listening experience is. So I would say those albums are more historically important (revolutionary, even) and pretty good in their own right, but, for me, The Mountain is better than them.