もののAlthough, But, Even Though

ものの expresses contrast, similar to 'although' in English, showing that while one thing is true, another contradicts it. が also expresses contrast, but its nuance is weaker, and in some cases, it merely introduces a statement without implying contrast. が is more general, while ものの is more specific. Both are formal and more common in writing than in casual speech.

Both ものの and けれども can appear at the end of a clause to show contrast. けれども (or the casual けど) usually expresses a simple contrast or adds background information, and is used in a wide range of situations. In contrast, ものの has the specific nuance of 'While A is true, B is not,' and is less colloquial, more commonly found in writing or formal speech.

のに and ものの both express contrast, but differ in nuance and tone. のに is more casual and often conveys disappointment or regret. It can also end a sentence to imply 'If only (A)!'. ものの is more formal and means 'although (A), (B) didn't follow as expected,' often with an implicit contrast. Unlike のに, it is not generally used alone at the end of a sentence..

Both ものの and 割に express contrast, but in different ways. ものの links two opposing facts to mean 'despite', e.g. '話せるものの、字は読めない' ('Despite the fact that he can speak, he can't read characters'). 割に describes a quality being out of proportion with something else, e.g. '高い割にはあまり美味しくない' ('For being expensive, it's not very tasty').