You are perfectly correct in that no translation is ever as good as the original; given the nature of language, it can hardly be otherwise.

I have read at least a half dozen translations of Dante's Divine Comedy including those of John Ciardi and Dorothy Sayers, which are accounted amoung the best, but have never read any which I thought really did justice to Dante's language.

However, there have been some really successful translations, which amount to a work of genius on the part of the translator. Bocaccio's Decameron is one of my favorite works of literature and I have two translations at home, one in ordinary English, which is quite good, and the other in pseudo-Elizabethan English, which is inspired. The name of this genius translator escapes me at the moment. I call it pseudo-Elizabethan because while it's intended to sound like Elizabethan English, it was actually written at the end of the 19th century. The English is frequently as funny in its own right as the Italian is, when it's intended to be funny.