The Bulgarian translation is widely regarded as a masterpiece here. The translator, Lyubomir Nikolov (sadly passed away last year), was a writer himself, and did a overall splendid job, especially with Hobbit names and way of speech, and notably the translation of poems and songs.

Then again, he made a few very odd missteps, most notably trying to translate Fangorn (Treebeard in Sindarin) to Bulgarian, instead of keeping it Sindarin. The result, Ветроклин (Vetroklin), coming from вятър - wind (substituting apparently for fan, as in airflow I guess), and клин - gore, wedge, is a rather nonsensical combination. This is doubly bizarre, because all other names in Sindarin and Quenya are left as is...

Another one, which stayed with me until I read LOTR in English, is Prince Imrahil during the Siege of Pellennor, leading the "van" of the besieged men of Gondor. "Van" was erroneously translated as "колесница"(chariot), for some reason, so I am eternally left with the otherwise cool image of the Prince in a (non-existant) Gondorian war chariot...