Dear Urpi,
In general, I agree with the other contributors.
Oxford English Dictionary --- �The� (6) Used adverbially with comparatives to indicate how one amount or degree varies in relation to another: �The more she thought about it, the more devastating it became�.
(Usually �all the ---�) used to emphasise the amount or degree to which something is affected: �Commodities made all the more desirable by their rarity�.
Another phrase which comes to me is: �The sooner, the better!� (�We must perform the action as soon as possible, because it is obvious that the result will be better for everyone. So we must not delay, and have a worse result�.)
There is a children�s story, "Little Red Riding Hood". The Big Bad Wolf is disguised as the Grandmother.
Little Red Riding Hood: "Oh, Grandma! What big eyes you have!"
Big Bad Wolf: "All the better to see you with!"
Little Red Riding Hood: "Oh, Grandma! What big ears you have!"
Big Bad Wolf: "All the better to hear you with!"
Little Red Riding Hood: "But, Grandma! What big teeth you have!"
Big Bad Wolf: "All the better to EAT YOU UP!"
Let us look at your first sentence. �The party was all the better for you being there�. (�Because you were there, the party was a better party than if you had not been there�
I am pedantic, so I would say: �The party was all the better for your being there�, (Because you were there, the party was all the better for your presence/your visit/your appearance).
Quirk and others, (2010, p 1063-1064), �A Comprehensive Grammar of the English language�, give similar constructions --- �I intend to voice my objections to their receiving an invitation to our meeting�. (I intend to voice my objections to their receipt of an invitation to our meeting.) �Your driving a car to New York took longer than I expected�. (Your journey to New York took longer than I expected�.)
I find myself in some difficulty when I read your second sentence. �Maria is one of the nicer people I know�.
My immediate reaction is: �Nicer in comparison with which other person?� Admittedly, �nicer� is qualified by �one of the�, so she has several friends who are �nicer� than others.
When I read this as an isolated sentence, without any other information, it says to me:
�I know several people. The majority of them are unpleasant.
�However, some of them are not as unpleasant as the others. These people are nicer than the unpleasant people.
�One such person is Maria. She is one of the nicer people I know.
�However, my nicest friend is XYZ. She is the very best person that I know�.
I tend to see Comparatives as a comparison between 2 people or things; but Superlatives as a choice of the best, (or worst), from a group of 3 or more.
However, the Superlative is not necessarily just 1 person or thing, but can be more than 1 person or thing. For example: �The best things in life are free!�
Also, I think we could say: �I have lots of nice friends, but my nicest friends are Sonia and Peter, because ... ,� (for example).
I am with Apodo, who says:��one of the nicest � is probably heard more often in modern informal English�.
In conversation, I would say: �One of the nicest people I know is ABC�. These are just my thoughts.
Les
