♥♦♣♠ NOT A TEACHER ♥♦♣♠
With my knowledge primarily based on the sources I am in possession of, all I can say on the topic is that no in place of not is stronger, as is the case in many other similar kinds of sentences with no in place of not a/an/any.
Perhaps I am being less than competent this evening, engee, but my quick look through OALD, Collins Cobuild English Grammar and Collins Cobuild English Usage turned up no reference to 'no' being stronger than 'not'. Could you give page references, please?
Something still unclear to me is (I might have misunderstood) that if "no more" or "no taller"'s no is a simple negation of the comparative, then when you negate something, it usually contains the other parts except the negated part, so the definition is somewhat confusing.
I mean no taller may mean the other parts excepts taller -> equal or shorter. I know you also said in the sense of as~as, but negation and as~as are contradicting each other.
I think that's why my grammar book says it has zero meaning, which is similar to my opinion "there is no fact from this". I think "no taller than John" means "from John's status I have nothing liker being taller", so no is not negation but the absence of something from the compared object.
I read 2. as having (a strongly stressed) implication (that 1. lacks) that Paris is not beautiful. So there is an equation of how beautiful Prague and Paris are:
Prague is no more beautiful than Paris = Prague is as (not beautiful) as Paris.
I see two problems in addition to the four I have already noted (which probably means that it's time to stop ):
1. I think that we are talking about feeling here, rather than anything that can be settled by resort to 'rules of grammar'.
2. If we are talking about feeling, then, apart from Philo, whose reliance on formal logic does not, in my opinion, help when we are talking about a living language, I am the only native speaker taking part in this discussion. It would be useful to see what other native speakers feel.
That penultimate sentence is not intended as any negative reflection on the opinions expressed by you and BC, both of whom have shown in this forum an understanding of English grammar superior to that of many native speakers.